* [PATCH RFC] Improve the performance of --num-threads -d 31
@ 2016-01-18 2:00 Zhou Wenjian
2016-01-18 5:09 ` "Zhou, Wenjian/周文剑"
2016-01-22 4:53 ` Atsushi Kumagai
0 siblings, 2 replies; 3+ messages in thread
From: Zhou Wenjian @ 2016-01-18 2:00 UTC (permalink / raw)
To: kexec
The origin implementation of --num-threads wastes a lot of time
dealing with the filtered pages. So it has a great performance degradation
when -d 31 is specified.
The new implementation is just like the following:
* The basic idea is producer producing page and consumer writing page.
* Each producer have a page_flag_buf list which is used for storing page's description.
* The size of page_flag_buf is little so it won't take too much memory.
* And all producers will share a page_data_buf array which is used for storing page's compressed data.
* The main thread is the consumer. It will find the next pfn and write it into file.
* The next pfn is smallest pfn in all page_flag_buf.
It won't waste time and memory for filtered page. So it has a good behaviour in -d 31.
Some tests results:
-l -c
-d 31: 2.6 11.3 (without num-threads)
num-threads origin new origin new
1 13.2 2.9 22.4 13.2
2 11.6 2.46 15.3 7.3
4 10.4 3.2 12.3 5.7
-d 0: 32.7 151.2(without num-threads)
1 43.3 45.3 158.9 159.4
2 21.2 23.0 81.8 83.2
4 18.2 21.4 46.1 47.5
These tests are executed in the second kernel with /proc/vmcore.
---
makedumpfile.c | 266 +++++++++++++++++++++++++++++++++++++++------------------
makedumpfile.h | 26 +++---
2 files changed, 196 insertions(+), 96 deletions(-)
diff --git a/makedumpfile.c b/makedumpfile.c
index fa0b779..8cf274b 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -3483,7 +3483,8 @@ initial_for_parallel()
unsigned long page_data_buf_size;
unsigned long limit_size;
int page_data_num;
- int i;
+ struct page_flag *current;
+ int i, j;
len_buf_out = calculate_len_buf_out(info->page_size);
@@ -3562,8 +3563,10 @@ initial_for_parallel()
- MAP_REGION * info->num_threads) * 0.6;
page_data_num = limit_size / page_data_buf_size;
+ info->num_buffers = 3 * info->num_threads;
- info->num_buffers = MIN(NUM_BUFFERS, page_data_num);
+ info->num_buffers = MAX(info->num_buffers, NUM_BUFFERS);
+ info->num_buffers = MIN(info->num_buffers, page_data_num);
DEBUG_MSG("Number of struct page_data for produce/consume: %d\n",
info->num_buffers);
@@ -3588,6 +3591,36 @@ initial_for_parallel()
}
/*
+ * initial page_flag for each thread
+ */
+ if ((info->page_flag_buf = malloc(sizeof(void *) * info->num_threads))
+ == NULL) {
+ MSG("Can't allocate memory for page_flag_buf. %s\n",
+ strerror(errno));
+ return FALSE;
+ }
+ memset(info->page_flag_buf, 0, sizeof(void *) * info->num_threads);
+
+ for (i = 0; i < info->num_threads; i++) {
+ if ((info->page_flag_buf[i] = malloc(sizeof(struct page_flag))) == NULL) {
+ MSG("Can't allocate memory for page_flag_buf. %s\n",
+ strerror(errno));
+ return FALSE;
+ }
+ current = info->page_flag_buf[i];
+
+ for (j = 1; j < NUM_BUFFERS; j++) {
+ if ((current->next = calloc(0, sizeof(struct page_flag))) == NULL) {
+ MSG("Can't allocate memory for data of page_data_buf. %s\n",
+ strerror(errno));
+ return FALSE;
+ }
+ current = current->next;
+ }
+ current->next = info->page_flag_buf[i];
+ }
+
+ /*
* initial fd_memory for threads
*/
for (i = 0; i < info->num_threads; i++) {
@@ -3612,7 +3645,8 @@ initial_for_parallel()
void
free_for_parallel()
{
- int i;
+ int i, j;
+ struct page_flag *current;
if (info->threads != NULL) {
for (i = 0; i < info->num_threads; i++) {
@@ -3655,6 +3689,19 @@ free_for_parallel()
free(info->page_data_buf);
}
+ if (info->page_flag_buf != NULL) {
+ for (i = 0; i < info->num_threads; i++) {
+ for (j = 0; j < NUM_BUFFERS; j++) {
+ if (info->page_flag_buf[i] != NULL) {
+ current = info->page_flag_buf[i];
+ info->page_flag_buf[i] = current->next;
+ free(current);
+ }
+ }
+ }
+ free(info->page_flag_buf);
+ }
+
if (info->parallel_info == NULL)
return;
@@ -7076,10 +7123,10 @@ kdump_thread_function_cyclic(void *arg) {
void *retval = PTHREAD_FAIL;
struct thread_args *kdump_thread_args = (struct thread_args *)arg;
struct page_data *page_data_buf = kdump_thread_args->page_data_buf;
+ struct page_flag *page_flag_buf = kdump_thread_args->page_flag_buf;
struct cycle *cycle = kdump_thread_args->cycle;
- int page_data_num = kdump_thread_args->page_data_num;
mdf_pfn_t pfn;
- int index;
+ int index = kdump_thread_args->thread_num;
int buf_ready;
int dumpable;
int fd_memory = 0;
@@ -7125,47 +7172,48 @@ kdump_thread_function_cyclic(void *arg) {
kdump_thread_args->thread_num);
}
- while (1) {
- /* get next pfn */
- pthread_mutex_lock(&info->current_pfn_mutex);
- pfn = info->current_pfn;
- info->current_pfn++;
- pthread_mutex_unlock(&info->current_pfn_mutex);
+ /* filtered page won't take anything
+ * unfiltered zero page will only take a page_flag_buf
+ * unfiltered non-zero page will take a page_flag_buf and a page_data_buf
+ */
+ while (page_flag_buf->pfn < kdump_thread_args->end_pfn) {
+ buf_ready = FALSE;
- if (pfn >= kdump_thread_args->end_pfn)
- break;
+ while (page_data_buf[index].used != 0 ||
+ pthread_mutex_trylock(&page_data_buf[index].mutex) != 0)
+ index = (index + 1) % info->num_buffers;
- index = -1;
- buf_ready = FALSE;
+ page_data_buf[index].used = 1;
while (buf_ready == FALSE) {
pthread_testcancel();
-
- index = pfn % page_data_num;
-
- if (pfn - info->consumed_pfn > info->num_buffers)
- continue;
-
- if (page_data_buf[index].ready != 0)
+ /* 1 means page_flag_buf is ready to be used */
+ if (page_flag_buf->ready == 1)
continue;
- pthread_mutex_lock(&page_data_buf[index].mutex);
+ /* get next pfn */
+ pthread_mutex_lock(&info->current_pfn_mutex);
+ pfn = info->current_pfn;
+ info->current_pfn++;
+ /* 2 means page_flag_buf is being filled */
+ page_flag_buf->ready = 2;
+ pthread_mutex_unlock(&info->current_pfn_mutex);
- if (page_data_buf[index].ready != 0)
- goto unlock;
+ page_flag_buf->pfn = pfn;
- buf_ready = TRUE;
-
- page_data_buf[index].pfn = pfn;
- page_data_buf[index].ready = 1;
+ if (pfn >= kdump_thread_args->end_pfn) {
+ page_data_buf[index].used = 0;
+ page_flag_buf->ready = 1;
+ info->current_pfn--;
+ break;
+ }
dumpable = is_dumpable(
info->fd_bitmap ? &bitmap_parallel : info->bitmap2,
pfn,
cycle);
- page_data_buf[index].dumpable = dumpable;
if (!dumpable)
- goto unlock;
+ continue;
if (!read_pfn_parallel(fd_memory, pfn, buf,
&bitmap_memory_parallel,
@@ -7178,11 +7226,11 @@ kdump_thread_function_cyclic(void *arg) {
if ((info->dump_level & DL_EXCLUDE_ZERO)
&& is_zero_page(buf, info->page_size)) {
- page_data_buf[index].zero = TRUE;
- goto unlock;
+ page_flag_buf->zero = TRUE;
+ goto next;
}
- page_data_buf[index].zero = FALSE;
+ page_flag_buf->zero = FALSE;
/*
* Compress the page data.
@@ -7232,12 +7280,16 @@ kdump_thread_function_cyclic(void *arg) {
page_data_buf[index].size = info->page_size;
memcpy(page_data_buf[index].buf, buf, info->page_size);
}
-unlock:
- pthread_mutex_unlock(&page_data_buf[index].mutex);
+ page_flag_buf->index = index;
+ buf_ready = TRUE;
+next:
+ page_flag_buf->ready = 1;
+ page_flag_buf = page_flag_buf->next;
}
- }
+ pthread_mutex_unlock(&page_data_buf[index].mutex);
+ }
retval = NULL;
fail:
@@ -7265,14 +7317,15 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
struct page_desc pd;
struct timeval tv_start;
struct timeval last, new;
- unsigned long long consuming_pfn;
pthread_t **threads = NULL;
struct thread_args *kdump_thread_args = NULL;
void *thread_result;
- int page_data_num;
+ int page_buf_num;
struct page_data *page_data_buf = NULL;
int i;
int index;
+ int end_count, consuming, check_count;
+ mdf_pfn_t current_pfn, temp_pfn;
if (info->flag_elf_dumpfile)
return FALSE;
@@ -7319,16 +7372,11 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
threads = info->threads;
kdump_thread_args = info->kdump_thread_args;
- page_data_num = info->num_buffers;
+ page_buf_num = info->num_buffers;
page_data_buf = info->page_data_buf;
- for (i = 0; i < page_data_num; i++) {
- /*
- * producer will use pfn in page_data_buf to decide the
- * consumed pfn
- */
- page_data_buf[i].pfn = start_pfn - 1;
- page_data_buf[i].ready = 0;
+ for (i = 0; i < page_buf_num; i++) {
+ page_data_buf[i].used = 0;
res = pthread_mutex_init(&page_data_buf[i].mutex, NULL);
if (res != 0) {
ERRMSG("Can't initialize mutex of page_data_buf. %s\n",
@@ -7342,8 +7390,9 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
kdump_thread_args[i].len_buf_out = len_buf_out;
kdump_thread_args[i].start_pfn = start_pfn;
kdump_thread_args[i].end_pfn = end_pfn;
- kdump_thread_args[i].page_data_num = page_data_num;
+ kdump_thread_args[i].page_buf_num = page_buf_num;
kdump_thread_args[i].page_data_buf = page_data_buf;
+ kdump_thread_args[i].page_flag_buf = info->page_flag_buf[i];
kdump_thread_args[i].cycle = cycle;
res = pthread_create(threads[i], NULL,
@@ -7356,55 +7405,101 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
}
}
- consuming_pfn = start_pfn;
- index = -1;
+ while (1) {
+ consuming = 0;
+ check_count = 0;
- gettimeofday(&last, NULL);
+ /*
+ * The basic idea is producer producing page and consumer writing page.
+ * Each producer have a page_flag_buf list which is used for storing page's description.
+ * The size of page_flag_buf is little so it won't take too much memory.
+ * And all producers will share a page_data_buf array which is used for storing page's compressed data.
+ * The main thread is the consumer. It will find the next pfn and write it into file.
+ * The next pfn is smallest pfn in all page_flag_buf.
+ */
+ /*
+ *
+ */
+ while (1) {
+ current_pfn = end_pfn;
+ end_count = 0;
- while (consuming_pfn < end_pfn) {
- index = consuming_pfn % page_data_num;
+ /*
+ * page_flag_buf is in circular linked list.
+ * The array info->page_flag_buf[] records the current page_flag_buf in each thread's
+ * page_flag_buf list.
+ * consuming is used for recording in which thread the pfn is the smallest.
+ * current_pfn is used for recording the value of pfn when checking the pfn.
+ */
+ for (i = 0; i < info->num_threads; i++) {
- gettimeofday(&new, NULL);
- if (new.tv_sec - last.tv_sec > WAIT_TIME) {
- ERRMSG("Can't get data of pfn %llx.\n", consuming_pfn);
- goto out;
- }
+ /*
+ * ready == 0 means the page_flag_buf haven't been used.
+ * So we will skip it.
+ */
+ if (info->page_flag_buf[i]->ready == 0)
+ continue;
+ temp_pfn = info->page_flag_buf[i]->pfn;
- /*
- * check pfn first without mutex locked to reduce the time
- * trying to lock the mutex
- */
- if (page_data_buf[index].pfn != consuming_pfn)
- continue;
+ /*
+ * count how many threads have reached the end.
+ */
+ if (temp_pfn >= end_pfn) {
+ end_count++;
+ continue;
+ }
- if (pthread_mutex_trylock(&page_data_buf[index].mutex) != 0)
- continue;
+ if (current_pfn < temp_pfn)
+ continue;
- /* check whether the found one is ready to be consumed */
- if (page_data_buf[index].pfn != consuming_pfn ||
- page_data_buf[index].ready != 1) {
- goto unlock;
+ check_count++;
+ consuming = i;
+ current_pfn = temp_pfn;
+ }
+
+ /*
+ * If all the threads have reached the end, we will finish writing.
+ */
+ if (end_count >= info->num_threads)
+ goto finish;
+
+ /*
+ * Since it has the probabilty that there is no page_flag_buf being ready,
+ * we should recheck if it happens.
+ */
+ if (check_count == 0)
+ continue;
+
+ /*
+ * When we check the pfn in page_flag_buf, it may be being produced.
+ * So we should wait until it is ready to use. And if the pfn is
+ * different from the value when we check, we should rechoose the buf.
+ */
+ gettimeofday(&last, NULL);
+ while (info->page_flag_buf[consuming]->ready != 1) {
+ gettimeofday(&new, NULL);
+ if (new.tv_sec - last.tv_sec > WAIT_TIME) {
+ ERRMSG("Can't get data of pfn.\n");
+ goto out;
+ }
+ }
+
+ if (current_pfn == info->page_flag_buf[consuming]->pfn)
+ break;
}
if ((num_dumped % per) == 0)
print_progress(PROGRESS_COPY, num_dumped, info->num_dumpable);
- /* next pfn is found, refresh last here */
- last = new;
- consuming_pfn++;
- info->consumed_pfn++;
- page_data_buf[index].ready = 0;
-
- if (page_data_buf[index].dumpable == FALSE)
- goto unlock;
-
num_dumped++;
- if (page_data_buf[index].zero == TRUE) {
+
+ if (info->page_flag_buf[consuming]->zero == TRUE) {
if (!write_cache(cd_header, pd_zero, sizeof(page_desc_t)))
goto out;
pfn_zero++;
} else {
+ index = info->page_flag_buf[consuming]->index;
pd.flags = page_data_buf[index].flags;
pd.size = page_data_buf[index].size;
pd.page_flags = 0;
@@ -7420,12 +7515,12 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
*/
if (!write_cache(cd_page, page_data_buf[index].buf, pd.size))
goto out;
-
+ page_data_buf[index].used = 0;
}
-unlock:
- pthread_mutex_unlock(&page_data_buf[index].mutex);
+ info->page_flag_buf[consuming]->ready = 0;
+ info->page_flag_buf[consuming] = info->page_flag_buf[consuming]->next;
}
-
+finish:
ret = TRUE;
/*
* print [100 %]
@@ -7464,7 +7559,7 @@ out:
}
if (page_data_buf != NULL) {
- for (i = 0; i < page_data_num; i++) {
+ for (i = 0; i < page_buf_num; i++) {
pthread_mutex_destroy(&page_data_buf[i].mutex);
}
}
@@ -7564,6 +7659,7 @@ write_kdump_pages_cyclic(struct cache_data *cd_header, struct cache_data *cd_pag
num_dumped++;
if (!read_pfn(pfn, buf))
goto out;
+
filter_data_buffer(buf, pfn_to_paddr(pfn), info->page_size);
/*
diff --git a/makedumpfile.h b/makedumpfile.h
index e0b5bbf..7452e24 100644
--- a/makedumpfile.h
+++ b/makedumpfile.h
@@ -977,7 +977,7 @@ typedef unsigned long long int ulonglong;
#define PAGE_DATA_NUM (50)
#define WAIT_TIME (60 * 10)
#define PTHREAD_FAIL ((void *)-2)
-#define NUM_BUFFERS (50)
+#define NUM_BUFFERS (20)
struct mmap_cache {
char *mmap_buf;
@@ -985,28 +985,31 @@ struct mmap_cache {
off_t mmap_end_offset;
};
+struct page_flag {
+ mdf_pfn_t pfn;
+ char zero;
+ char ready;
+ short index;
+ struct page_flag *next;
+};
+
struct page_data
{
- mdf_pfn_t pfn;
- int dumpable;
- int zero;
- unsigned int flags;
+ pthread_mutex_t mutex;
long size;
unsigned char *buf;
- pthread_mutex_t mutex;
- /*
- * whether the page_data is ready to be consumed
- */
- int ready;
+ int flags;
+ int used;
};
struct thread_args {
int thread_num;
unsigned long len_buf_out;
mdf_pfn_t start_pfn, end_pfn;
- int page_data_num;
+ int page_buf_num;
struct cycle *cycle;
struct page_data *page_data_buf;
+ struct page_flag *page_flag_buf;
};
/*
@@ -1295,6 +1298,7 @@ struct DumpInfo {
pthread_t **threads;
struct thread_args *kdump_thread_args;
struct page_data *page_data_buf;
+ struct page_flag **page_flag_buf;
pthread_rwlock_t usemmap_rwlock;
mdf_pfn_t current_pfn;
pthread_mutex_t current_pfn_mutex;
--
1.8.3.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH RFC] Improve the performance of --num-threads -d 31
2016-01-18 2:00 [PATCH RFC] Improve the performance of --num-threads -d 31 Zhou Wenjian
@ 2016-01-18 5:09 ` "Zhou, Wenjian/周文剑"
2016-01-22 4:53 ` Atsushi Kumagai
1 sibling, 0 replies; 3+ messages in thread
From: "Zhou, Wenjian/周文剑" @ 2016-01-18 5:09 UTC (permalink / raw)
To: kexec; +Cc: Chao Fan, Atsushi Kumagai, Dave Young, HATAYAMA Daisuke
Hello,
Several weeks ago, we talked about the performance degradation of --num-threads 1.
I found in the origin implementation, handling filtered page and zero page spends more
time than without num-threads.
I think that's why --num-threads 1 is so different from --num-threads 0.
I rewrite the logic in this patch. And the new implementation can resolve the degradation
of -d 31. It can reduce the time of handling filtered page.
But it seems not effective for handling zero page.
--
Thanks
Zhou
On 01/18/2016 10:00 AM, Zhou Wenjian wrote:
> The origin implementation of --num-threads wastes a lot of time
> dealing with the filtered pages. So it has a great performance degradation
> when -d 31 is specified.
> The new implementation is just like the following:
> * The basic idea is producer producing page and consumer writing page.
> * Each producer have a page_flag_buf list which is used for storing page's description.
> * The size of page_flag_buf is little so it won't take too much memory.
> * And all producers will share a page_data_buf array which is used for storing page's compressed data.
> * The main thread is the consumer. It will find the next pfn and write it into file.
> * The next pfn is smallest pfn in all page_flag_buf.
> It won't waste time and memory for filtered page. So it has a good behaviour in -d 31.
>
> Some tests results:
>
> -l -c
> -d 31: 2.6 11.3 (without num-threads)
> num-threads origin new origin new
> 1 13.2 2.9 22.4 13.2
> 2 11.6 2.46 15.3 7.3
> 4 10.4 3.2 12.3 5.7
> -d 0: 32.7 151.2(without num-threads)
> 1 43.3 45.3 158.9 159.4
> 2 21.2 23.0 81.8 83.2
> 4 18.2 21.4 46.1 47.5
>
> These tests are executed in the second kernel with /proc/vmcore.
> ---
> makedumpfile.c | 266 +++++++++++++++++++++++++++++++++++++++------------------
> makedumpfile.h | 26 +++---
> 2 files changed, 196 insertions(+), 96 deletions(-)
>
> diff --git a/makedumpfile.c b/makedumpfile.c
> index fa0b779..8cf274b 100644
> --- a/makedumpfile.c
> +++ b/makedumpfile.c
> @@ -3483,7 +3483,8 @@ initial_for_parallel()
> unsigned long page_data_buf_size;
> unsigned long limit_size;
> int page_data_num;
> - int i;
> + struct page_flag *current;
> + int i, j;
>
> len_buf_out = calculate_len_buf_out(info->page_size);
>
> @@ -3562,8 +3563,10 @@ initial_for_parallel()
> - MAP_REGION * info->num_threads) * 0.6;
>
> page_data_num = limit_size / page_data_buf_size;
> + info->num_buffers = 3 * info->num_threads;
>
> - info->num_buffers = MIN(NUM_BUFFERS, page_data_num);
> + info->num_buffers = MAX(info->num_buffers, NUM_BUFFERS);
> + info->num_buffers = MIN(info->num_buffers, page_data_num);
>
> DEBUG_MSG("Number of struct page_data for produce/consume: %d\n",
> info->num_buffers);
> @@ -3588,6 +3591,36 @@ initial_for_parallel()
> }
>
> /*
> + * initial page_flag for each thread
> + */
> + if ((info->page_flag_buf = malloc(sizeof(void *) * info->num_threads))
> + == NULL) {
> + MSG("Can't allocate memory for page_flag_buf. %s\n",
> + strerror(errno));
> + return FALSE;
> + }
> + memset(info->page_flag_buf, 0, sizeof(void *) * info->num_threads);
> +
> + for (i = 0; i < info->num_threads; i++) {
> + if ((info->page_flag_buf[i] = malloc(sizeof(struct page_flag))) == NULL) {
> + MSG("Can't allocate memory for page_flag_buf. %s\n",
> + strerror(errno));
> + return FALSE;
> + }
> + current = info->page_flag_buf[i];
> +
> + for (j = 1; j < NUM_BUFFERS; j++) {
> + if ((current->next = calloc(0, sizeof(struct page_flag))) == NULL) {
> + MSG("Can't allocate memory for data of page_data_buf. %s\n",
> + strerror(errno));
> + return FALSE;
> + }
> + current = current->next;
> + }
> + current->next = info->page_flag_buf[i];
> + }
> +
> + /*
> * initial fd_memory for threads
> */
> for (i = 0; i < info->num_threads; i++) {
> @@ -3612,7 +3645,8 @@ initial_for_parallel()
> void
> free_for_parallel()
> {
> - int i;
> + int i, j;
> + struct page_flag *current;
>
> if (info->threads != NULL) {
> for (i = 0; i < info->num_threads; i++) {
> @@ -3655,6 +3689,19 @@ free_for_parallel()
> free(info->page_data_buf);
> }
>
> + if (info->page_flag_buf != NULL) {
> + for (i = 0; i < info->num_threads; i++) {
> + for (j = 0; j < NUM_BUFFERS; j++) {
> + if (info->page_flag_buf[i] != NULL) {
> + current = info->page_flag_buf[i];
> + info->page_flag_buf[i] = current->next;
> + free(current);
> + }
> + }
> + }
> + free(info->page_flag_buf);
> + }
> +
> if (info->parallel_info == NULL)
> return;
>
> @@ -7076,10 +7123,10 @@ kdump_thread_function_cyclic(void *arg) {
> void *retval = PTHREAD_FAIL;
> struct thread_args *kdump_thread_args = (struct thread_args *)arg;
> struct page_data *page_data_buf = kdump_thread_args->page_data_buf;
> + struct page_flag *page_flag_buf = kdump_thread_args->page_flag_buf;
> struct cycle *cycle = kdump_thread_args->cycle;
> - int page_data_num = kdump_thread_args->page_data_num;
> mdf_pfn_t pfn;
> - int index;
> + int index = kdump_thread_args->thread_num;
> int buf_ready;
> int dumpable;
> int fd_memory = 0;
> @@ -7125,47 +7172,48 @@ kdump_thread_function_cyclic(void *arg) {
> kdump_thread_args->thread_num);
> }
>
> - while (1) {
> - /* get next pfn */
> - pthread_mutex_lock(&info->current_pfn_mutex);
> - pfn = info->current_pfn;
> - info->current_pfn++;
> - pthread_mutex_unlock(&info->current_pfn_mutex);
> + /* filtered page won't take anything
> + * unfiltered zero page will only take a page_flag_buf
> + * unfiltered non-zero page will take a page_flag_buf and a page_data_buf
> + */
> + while (page_flag_buf->pfn < kdump_thread_args->end_pfn) {
> + buf_ready = FALSE;
>
> - if (pfn >= kdump_thread_args->end_pfn)
> - break;
> + while (page_data_buf[index].used != 0 ||
> + pthread_mutex_trylock(&page_data_buf[index].mutex) != 0)
> + index = (index + 1) % info->num_buffers;
>
> - index = -1;
> - buf_ready = FALSE;
> + page_data_buf[index].used = 1;
>
> while (buf_ready == FALSE) {
> pthread_testcancel();
> -
> - index = pfn % page_data_num;
> -
> - if (pfn - info->consumed_pfn > info->num_buffers)
> - continue;
> -
> - if (page_data_buf[index].ready != 0)
> + /* 1 means page_flag_buf is ready to be used */
> + if (page_flag_buf->ready == 1)
> continue;
>
> - pthread_mutex_lock(&page_data_buf[index].mutex);
> + /* get next pfn */
> + pthread_mutex_lock(&info->current_pfn_mutex);
> + pfn = info->current_pfn;
> + info->current_pfn++;
> + /* 2 means page_flag_buf is being filled */
> + page_flag_buf->ready = 2;
> + pthread_mutex_unlock(&info->current_pfn_mutex);
>
> - if (page_data_buf[index].ready != 0)
> - goto unlock;
> + page_flag_buf->pfn = pfn;
>
> - buf_ready = TRUE;
> -
> - page_data_buf[index].pfn = pfn;
> - page_data_buf[index].ready = 1;
> + if (pfn >= kdump_thread_args->end_pfn) {
> + page_data_buf[index].used = 0;
> + page_flag_buf->ready = 1;
> + info->current_pfn--;
> + break;
> + }
>
> dumpable = is_dumpable(
> info->fd_bitmap ? &bitmap_parallel : info->bitmap2,
> pfn,
> cycle);
> - page_data_buf[index].dumpable = dumpable;
> if (!dumpable)
> - goto unlock;
> + continue;
>
> if (!read_pfn_parallel(fd_memory, pfn, buf,
> &bitmap_memory_parallel,
> @@ -7178,11 +7226,11 @@ kdump_thread_function_cyclic(void *arg) {
>
> if ((info->dump_level & DL_EXCLUDE_ZERO)
> && is_zero_page(buf, info->page_size)) {
> - page_data_buf[index].zero = TRUE;
> - goto unlock;
> + page_flag_buf->zero = TRUE;
> + goto next;
> }
>
> - page_data_buf[index].zero = FALSE;
> + page_flag_buf->zero = FALSE;
>
> /*
> * Compress the page data.
> @@ -7232,12 +7280,16 @@ kdump_thread_function_cyclic(void *arg) {
> page_data_buf[index].size = info->page_size;
> memcpy(page_data_buf[index].buf, buf, info->page_size);
> }
> -unlock:
> - pthread_mutex_unlock(&page_data_buf[index].mutex);
> + page_flag_buf->index = index;
> + buf_ready = TRUE;
> +next:
> + page_flag_buf->ready = 1;
> + page_flag_buf = page_flag_buf->next;
>
> }
> - }
>
> + pthread_mutex_unlock(&page_data_buf[index].mutex);
> + }
> retval = NULL;
>
> fail:
> @@ -7265,14 +7317,15 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> struct page_desc pd;
> struct timeval tv_start;
> struct timeval last, new;
> - unsigned long long consuming_pfn;
> pthread_t **threads = NULL;
> struct thread_args *kdump_thread_args = NULL;
> void *thread_result;
> - int page_data_num;
> + int page_buf_num;
> struct page_data *page_data_buf = NULL;
> int i;
> int index;
> + int end_count, consuming, check_count;
> + mdf_pfn_t current_pfn, temp_pfn;
>
> if (info->flag_elf_dumpfile)
> return FALSE;
> @@ -7319,16 +7372,11 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> threads = info->threads;
> kdump_thread_args = info->kdump_thread_args;
>
> - page_data_num = info->num_buffers;
> + page_buf_num = info->num_buffers;
> page_data_buf = info->page_data_buf;
>
> - for (i = 0; i < page_data_num; i++) {
> - /*
> - * producer will use pfn in page_data_buf to decide the
> - * consumed pfn
> - */
> - page_data_buf[i].pfn = start_pfn - 1;
> - page_data_buf[i].ready = 0;
> + for (i = 0; i < page_buf_num; i++) {
> + page_data_buf[i].used = 0;
> res = pthread_mutex_init(&page_data_buf[i].mutex, NULL);
> if (res != 0) {
> ERRMSG("Can't initialize mutex of page_data_buf. %s\n",
> @@ -7342,8 +7390,9 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> kdump_thread_args[i].len_buf_out = len_buf_out;
> kdump_thread_args[i].start_pfn = start_pfn;
> kdump_thread_args[i].end_pfn = end_pfn;
> - kdump_thread_args[i].page_data_num = page_data_num;
> + kdump_thread_args[i].page_buf_num = page_buf_num;
> kdump_thread_args[i].page_data_buf = page_data_buf;
> + kdump_thread_args[i].page_flag_buf = info->page_flag_buf[i];
> kdump_thread_args[i].cycle = cycle;
>
> res = pthread_create(threads[i], NULL,
> @@ -7356,55 +7405,101 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> }
> }
>
> - consuming_pfn = start_pfn;
> - index = -1;
> + while (1) {
> + consuming = 0;
> + check_count = 0;
>
> - gettimeofday(&last, NULL);
> + /*
> + * The basic idea is producer producing page and consumer writing page.
> + * Each producer have a page_flag_buf list which is used for storing page's description.
> + * The size of page_flag_buf is little so it won't take too much memory.
> + * And all producers will share a page_data_buf array which is used for storing page's compressed data.
> + * The main thread is the consumer. It will find the next pfn and write it into file.
> + * The next pfn is smallest pfn in all page_flag_buf.
> + */
> + /*
> + *
> + */
> + while (1) {
> + current_pfn = end_pfn;
> + end_count = 0;
>
> - while (consuming_pfn < end_pfn) {
> - index = consuming_pfn % page_data_num;
> + /*
> + * page_flag_buf is in circular linked list.
> + * The array info->page_flag_buf[] records the current page_flag_buf in each thread's
> + * page_flag_buf list.
> + * consuming is used for recording in which thread the pfn is the smallest.
> + * current_pfn is used for recording the value of pfn when checking the pfn.
> + */
> + for (i = 0; i < info->num_threads; i++) {
>
> - gettimeofday(&new, NULL);
> - if (new.tv_sec - last.tv_sec > WAIT_TIME) {
> - ERRMSG("Can't get data of pfn %llx.\n", consuming_pfn);
> - goto out;
> - }
> + /*
> + * ready == 0 means the page_flag_buf haven't been used.
> + * So we will skip it.
> + */
> + if (info->page_flag_buf[i]->ready == 0)
> + continue;
> + temp_pfn = info->page_flag_buf[i]->pfn;
>
> - /*
> - * check pfn first without mutex locked to reduce the time
> - * trying to lock the mutex
> - */
> - if (page_data_buf[index].pfn != consuming_pfn)
> - continue;
> + /*
> + * count how many threads have reached the end.
> + */
> + if (temp_pfn >= end_pfn) {
> + end_count++;
> + continue;
> + }
>
> - if (pthread_mutex_trylock(&page_data_buf[index].mutex) != 0)
> - continue;
> + if (current_pfn < temp_pfn)
> + continue;
>
> - /* check whether the found one is ready to be consumed */
> - if (page_data_buf[index].pfn != consuming_pfn ||
> - page_data_buf[index].ready != 1) {
> - goto unlock;
> + check_count++;
> + consuming = i;
> + current_pfn = temp_pfn;
> + }
> +
> + /*
> + * If all the threads have reached the end, we will finish writing.
> + */
> + if (end_count >= info->num_threads)
> + goto finish;
> +
> + /*
> + * Since it has the probabilty that there is no page_flag_buf being ready,
> + * we should recheck if it happens.
> + */
> + if (check_count == 0)
> + continue;
> +
> + /*
> + * When we check the pfn in page_flag_buf, it may be being produced.
> + * So we should wait until it is ready to use. And if the pfn is
> + * different from the value when we check, we should rechoose the buf.
> + */
> + gettimeofday(&last, NULL);
> + while (info->page_flag_buf[consuming]->ready != 1) {
> + gettimeofday(&new, NULL);
> + if (new.tv_sec - last.tv_sec > WAIT_TIME) {
> + ERRMSG("Can't get data of pfn.\n");
> + goto out;
> + }
> + }
> +
> + if (current_pfn == info->page_flag_buf[consuming]->pfn)
> + break;
> }
>
> if ((num_dumped % per) == 0)
> print_progress(PROGRESS_COPY, num_dumped, info->num_dumpable);
>
> - /* next pfn is found, refresh last here */
> - last = new;
> - consuming_pfn++;
> - info->consumed_pfn++;
> - page_data_buf[index].ready = 0;
> -
> - if (page_data_buf[index].dumpable == FALSE)
> - goto unlock;
> -
> num_dumped++;
>
> - if (page_data_buf[index].zero == TRUE) {
> +
> + if (info->page_flag_buf[consuming]->zero == TRUE) {
> if (!write_cache(cd_header, pd_zero, sizeof(page_desc_t)))
> goto out;
> pfn_zero++;
> } else {
> + index = info->page_flag_buf[consuming]->index;
> pd.flags = page_data_buf[index].flags;
> pd.size = page_data_buf[index].size;
> pd.page_flags = 0;
> @@ -7420,12 +7515,12 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> */
> if (!write_cache(cd_page, page_data_buf[index].buf, pd.size))
> goto out;
> -
> + page_data_buf[index].used = 0;
> }
> -unlock:
> - pthread_mutex_unlock(&page_data_buf[index].mutex);
> + info->page_flag_buf[consuming]->ready = 0;
> + info->page_flag_buf[consuming] = info->page_flag_buf[consuming]->next;
> }
> -
> +finish:
> ret = TRUE;
> /*
> * print [100 %]
> @@ -7464,7 +7559,7 @@ out:
> }
>
> if (page_data_buf != NULL) {
> - for (i = 0; i < page_data_num; i++) {
> + for (i = 0; i < page_buf_num; i++) {
> pthread_mutex_destroy(&page_data_buf[i].mutex);
> }
> }
> @@ -7564,6 +7659,7 @@ write_kdump_pages_cyclic(struct cache_data *cd_header, struct cache_data *cd_pag
> num_dumped++;
> if (!read_pfn(pfn, buf))
> goto out;
> +
> filter_data_buffer(buf, pfn_to_paddr(pfn), info->page_size);
>
> /*
> diff --git a/makedumpfile.h b/makedumpfile.h
> index e0b5bbf..7452e24 100644
> --- a/makedumpfile.h
> +++ b/makedumpfile.h
> @@ -977,7 +977,7 @@ typedef unsigned long long int ulonglong;
> #define PAGE_DATA_NUM (50)
> #define WAIT_TIME (60 * 10)
> #define PTHREAD_FAIL ((void *)-2)
> -#define NUM_BUFFERS (50)
> +#define NUM_BUFFERS (20)
>
> struct mmap_cache {
> char *mmap_buf;
> @@ -985,28 +985,31 @@ struct mmap_cache {
> off_t mmap_end_offset;
> };
>
> +struct page_flag {
> + mdf_pfn_t pfn;
> + char zero;
> + char ready;
> + short index;
> + struct page_flag *next;
> +};
> +
> struct page_data
> {
> - mdf_pfn_t pfn;
> - int dumpable;
> - int zero;
> - unsigned int flags;
> + pthread_mutex_t mutex;
> long size;
> unsigned char *buf;
> - pthread_mutex_t mutex;
> - /*
> - * whether the page_data is ready to be consumed
> - */
> - int ready;
> + int flags;
> + int used;
> };
>
> struct thread_args {
> int thread_num;
> unsigned long len_buf_out;
> mdf_pfn_t start_pfn, end_pfn;
> - int page_data_num;
> + int page_buf_num;
> struct cycle *cycle;
> struct page_data *page_data_buf;
> + struct page_flag *page_flag_buf;
> };
>
> /*
> @@ -1295,6 +1298,7 @@ struct DumpInfo {
> pthread_t **threads;
> struct thread_args *kdump_thread_args;
> struct page_data *page_data_buf;
> + struct page_flag **page_flag_buf;
> pthread_rwlock_t usemmap_rwlock;
> mdf_pfn_t current_pfn;
> pthread_mutex_t current_pfn_mutex;
>
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^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: [PATCH RFC] Improve the performance of --num-threads -d 31
2016-01-18 2:00 [PATCH RFC] Improve the performance of --num-threads -d 31 Zhou Wenjian
2016-01-18 5:09 ` "Zhou, Wenjian/周文剑"
@ 2016-01-22 4:53 ` Atsushi Kumagai
1 sibling, 0 replies; 3+ messages in thread
From: Atsushi Kumagai @ 2016-01-22 4:53 UTC (permalink / raw)
To: zhouwj-fnst@cn.fujitsu.com; +Cc: kexec@lists.infradead.org
Hello Zhou,
>The origin implementation of --num-threads wastes a lot of time
>dealing with the filtered pages. So it has a great performance degradation
>when -d 31 is specified.
>The new implementation is just like the following:
> * The basic idea is producer producing page and consumer writing page.
> * Each producer have a page_flag_buf list which is used for storing page's description.
> * The size of page_flag_buf is little so it won't take too much memory.
> * And all producers will share a page_data_buf array which is used for storing page's compressed data.
> * The main thread is the consumer. It will find the next pfn and write it into file.
> * The next pfn is smallest pfn in all page_flag_buf.
>It won't waste time and memory for filtered page. So it has a good behaviour in -d 31.
>
>Some tests results:
>
> -l -c
>-d 31: 2.6 11.3 (without num-threads)
> num-threads origin new origin new
> 1 13.2 2.9 22.4 13.2
> 2 11.6 2.46 15.3 7.3
> 4 10.4 3.2 12.3 5.7
>-d 0: 32.7 151.2(without num-threads)
> 1 43.3 45.3 158.9 159.4
> 2 21.2 23.0 81.8 83.2
> 4 18.2 21.4 46.1 47.5
>
>These tests are executed in the second kernel with /proc/vmcore.
I appreciate your work, the effect looks great.
There are still some performance degradation depending on the dump level,
but the problem we discussed is "especially -d31 is too slow",
so I think this patch is enough for now.
BTW, I have some small comments for cleanup, please check below.
>---
> makedumpfile.c | 266 +++++++++++++++++++++++++++++++++++++++------------------
> makedumpfile.h | 26 +++---
> 2 files changed, 196 insertions(+), 96 deletions(-)
>
>diff --git a/makedumpfile.c b/makedumpfile.c
>index fa0b779..8cf274b 100644
>--- a/makedumpfile.c
>+++ b/makedumpfile.c
>@@ -3483,7 +3483,8 @@ initial_for_parallel()
> unsigned long page_data_buf_size;
> unsigned long limit_size;
> int page_data_num;
>- int i;
>+ struct page_flag *current;
>+ int i, j;
>
> len_buf_out = calculate_len_buf_out(info->page_size);
>
>@@ -3562,8 +3563,10 @@ initial_for_parallel()
> - MAP_REGION * info->num_threads) * 0.6;
>
> page_data_num = limit_size / page_data_buf_size;
>+ info->num_buffers = 3 * info->num_threads;
>
>- info->num_buffers = MIN(NUM_BUFFERS, page_data_num);
>+ info->num_buffers = MAX(info->num_buffers, NUM_BUFFERS);
>+ info->num_buffers = MIN(info->num_buffers, page_data_num);
>
> DEBUG_MSG("Number of struct page_data for produce/consume: %d\n",
> info->num_buffers);
>@@ -3588,6 +3591,36 @@ initial_for_parallel()
> }
>
> /*
>+ * initial page_flag for each thread
>+ */
>+ if ((info->page_flag_buf = malloc(sizeof(void *) * info->num_threads))
>+ == NULL) {
>+ MSG("Can't allocate memory for page_flag_buf. %s\n",
>+ strerror(errno));
>+ return FALSE;
>+ }
>+ memset(info->page_flag_buf, 0, sizeof(void *) * info->num_threads);
>+
>+ for (i = 0; i < info->num_threads; i++) {
>+ if ((info->page_flag_buf[i] = malloc(sizeof(struct page_flag))) == NULL) {
>+ MSG("Can't allocate memory for page_flag_buf. %s\n",
>+ strerror(errno));
>+ return FALSE;
>+ }
>+ current = info->page_flag_buf[i];
>+
>+ for (j = 1; j < NUM_BUFFERS; j++) {
>+ if ((current->next = calloc(0, sizeof(struct page_flag))) == NULL) {
>+ MSG("Can't allocate memory for data of page_data_buf. %s\n",
>+ strerror(errno));
>+ return FALSE;
>+ }
>+ current = current->next;
>+ }
>+ current->next = info->page_flag_buf[i];
>+ }
>+
>+ /*
> * initial fd_memory for threads
> */
> for (i = 0; i < info->num_threads; i++) {
>@@ -3612,7 +3645,8 @@ initial_for_parallel()
> void
> free_for_parallel()
> {
>- int i;
>+ int i, j;
>+ struct page_flag *current;
>
> if (info->threads != NULL) {
> for (i = 0; i < info->num_threads; i++) {
>@@ -3655,6 +3689,19 @@ free_for_parallel()
> free(info->page_data_buf);
> }
>
>+ if (info->page_flag_buf != NULL) {
>+ for (i = 0; i < info->num_threads; i++) {
>+ for (j = 0; j < NUM_BUFFERS; j++) {
>+ if (info->page_flag_buf[i] != NULL) {
>+ current = info->page_flag_buf[i];
>+ info->page_flag_buf[i] = current->next;
>+ free(current);
>+ }
>+ }
>+ }
>+ free(info->page_flag_buf);
>+ }
>+
> if (info->parallel_info == NULL)
> return;
>
>@@ -7076,10 +7123,10 @@ kdump_thread_function_cyclic(void *arg) {
> void *retval = PTHREAD_FAIL;
> struct thread_args *kdump_thread_args = (struct thread_args *)arg;
> struct page_data *page_data_buf = kdump_thread_args->page_data_buf;
>+ struct page_flag *page_flag_buf = kdump_thread_args->page_flag_buf;
> struct cycle *cycle = kdump_thread_args->cycle;
>- int page_data_num = kdump_thread_args->page_data_num;
> mdf_pfn_t pfn;
>- int index;
>+ int index = kdump_thread_args->thread_num;
> int buf_ready;
> int dumpable;
> int fd_memory = 0;
>@@ -7125,47 +7172,48 @@ kdump_thread_function_cyclic(void *arg) {
> kdump_thread_args->thread_num);
> }
>
>- while (1) {
>- /* get next pfn */
>- pthread_mutex_lock(&info->current_pfn_mutex);
>- pfn = info->current_pfn;
>- info->current_pfn++;
>- pthread_mutex_unlock(&info->current_pfn_mutex);
>+ /* filtered page won't take anything
>+ * unfiltered zero page will only take a page_flag_buf
>+ * unfiltered non-zero page will take a page_flag_buf and a page_data_buf
>+ */
>+ while (page_flag_buf->pfn < kdump_thread_args->end_pfn) {
>+ buf_ready = FALSE;
>
>- if (pfn >= kdump_thread_args->end_pfn)
>- break;
>+ while (page_data_buf[index].used != 0 ||
>+ pthread_mutex_trylock(&page_data_buf[index].mutex) != 0)
>+ index = (index + 1) % info->num_buffers;
>
>- index = -1;
>- buf_ready = FALSE;
>+ page_data_buf[index].used = 1;
>
> while (buf_ready == FALSE) {
> pthread_testcancel();
>-
>- index = pfn % page_data_num;
>-
>- if (pfn - info->consumed_pfn > info->num_buffers)
>- continue;
>-
>- if (page_data_buf[index].ready != 0)
>+ /* 1 means page_flag_buf is ready to be used */
>+ if (page_flag_buf->ready == 1)
> continue;
For status flag, enum is preferable to explaining a magic number by comment.
>
>- pthread_mutex_lock(&page_data_buf[index].mutex);
>+ /* get next pfn */
>+ pthread_mutex_lock(&info->current_pfn_mutex);
>+ pfn = info->current_pfn;
>+ info->current_pfn++;
>+ /* 2 means page_flag_buf is being filled */
>+ page_flag_buf->ready = 2;
>+ pthread_mutex_unlock(&info->current_pfn_mutex);
>
>- if (page_data_buf[index].ready != 0)
>- goto unlock;
>+ page_flag_buf->pfn = pfn;
>
>- buf_ready = TRUE;
>-
>- page_data_buf[index].pfn = pfn;
>- page_data_buf[index].ready = 1;
>+ if (pfn >= kdump_thread_args->end_pfn) {
>+ page_data_buf[index].used = 0;
>+ page_flag_buf->ready = 1;
>+ info->current_pfn--;
>+ break;
>+ }
>
> dumpable = is_dumpable(
> info->fd_bitmap ? &bitmap_parallel : info->bitmap2,
> pfn,
> cycle);
>- page_data_buf[index].dumpable = dumpable;
> if (!dumpable)
>- goto unlock;
>+ continue;
>
> if (!read_pfn_parallel(fd_memory, pfn, buf,
> &bitmap_memory_parallel,
>@@ -7178,11 +7226,11 @@ kdump_thread_function_cyclic(void *arg) {
>
> if ((info->dump_level & DL_EXCLUDE_ZERO)
> && is_zero_page(buf, info->page_size)) {
>- page_data_buf[index].zero = TRUE;
>- goto unlock;
>+ page_flag_buf->zero = TRUE;
>+ goto next;
> }
>
>- page_data_buf[index].zero = FALSE;
>+ page_flag_buf->zero = FALSE;
>
> /*
> * Compress the page data.
>@@ -7232,12 +7280,16 @@ kdump_thread_function_cyclic(void *arg) {
> page_data_buf[index].size = info->page_size;
> memcpy(page_data_buf[index].buf, buf, info->page_size);
> }
>-unlock:
>- pthread_mutex_unlock(&page_data_buf[index].mutex);
>+ page_flag_buf->index = index;
>+ buf_ready = TRUE;
>+next:
>+ page_flag_buf->ready = 1;
>+ page_flag_buf = page_flag_buf->next;
>
> }
>- }
>
>+ pthread_mutex_unlock(&page_data_buf[index].mutex);
>+ }
> retval = NULL;
>
> fail:
>@@ -7265,14 +7317,15 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> struct page_desc pd;
> struct timeval tv_start;
> struct timeval last, new;
>- unsigned long long consuming_pfn;
> pthread_t **threads = NULL;
> struct thread_args *kdump_thread_args = NULL;
> void *thread_result;
>- int page_data_num;
>+ int page_buf_num;
> struct page_data *page_data_buf = NULL;
> int i;
> int index;
>+ int end_count, consuming, check_count;
>+ mdf_pfn_t current_pfn, temp_pfn;
>
> if (info->flag_elf_dumpfile)
> return FALSE;
>@@ -7319,16 +7372,11 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> threads = info->threads;
> kdump_thread_args = info->kdump_thread_args;
>
>- page_data_num = info->num_buffers;
>+ page_buf_num = info->num_buffers;
> page_data_buf = info->page_data_buf;
>
>- for (i = 0; i < page_data_num; i++) {
>- /*
>- * producer will use pfn in page_data_buf to decide the
>- * consumed pfn
>- */
>- page_data_buf[i].pfn = start_pfn - 1;
>- page_data_buf[i].ready = 0;
>+ for (i = 0; i < page_buf_num; i++) {
>+ page_data_buf[i].used = 0;
> res = pthread_mutex_init(&page_data_buf[i].mutex, NULL);
> if (res != 0) {
> ERRMSG("Can't initialize mutex of page_data_buf. %s\n",
>@@ -7342,8 +7390,9 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> kdump_thread_args[i].len_buf_out = len_buf_out;
> kdump_thread_args[i].start_pfn = start_pfn;
> kdump_thread_args[i].end_pfn = end_pfn;
>- kdump_thread_args[i].page_data_num = page_data_num;
>+ kdump_thread_args[i].page_buf_num = page_buf_num;
> kdump_thread_args[i].page_data_buf = page_data_buf;
>+ kdump_thread_args[i].page_flag_buf = info->page_flag_buf[i];
> kdump_thread_args[i].cycle = cycle;
>
> res = pthread_create(threads[i], NULL,
>@@ -7356,55 +7405,101 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> }
> }
>
>- consuming_pfn = start_pfn;
>- index = -1;
>+ while (1) {
>+ consuming = 0;
>+ check_count = 0;
>
>- gettimeofday(&last, NULL);
>+ /*
>+ * The basic idea is producer producing page and consumer writing page.
>+ * Each producer have a page_flag_buf list which is used for storing page's description.
>+ * The size of page_flag_buf is little so it won't take too much memory.
>+ * And all producers will share a page_data_buf array which is used for storing page's compressed data.
>+ * The main thread is the consumer. It will find the next pfn and write it into file.
>+ * The next pfn is smallest pfn in all page_flag_buf.
>+ */
>+ /*
>+ *
>+ */
I hope such garbage will be removed in the next version.
Thanks,
Atsushi Kumagai
>+ while (1) {
>+ current_pfn = end_pfn;
>+ end_count = 0;
>
>- while (consuming_pfn < end_pfn) {
>- index = consuming_pfn % page_data_num;
>+ /*
>+ * page_flag_buf is in circular linked list.
>+ * The array info->page_flag_buf[] records the current page_flag_buf in each thread's
>+ * page_flag_buf list.
>+ * consuming is used for recording in which thread the pfn is the smallest.
>+ * current_pfn is used for recording the value of pfn when checking the pfn.
>+ */
>+ for (i = 0; i < info->num_threads; i++) {
>
>- gettimeofday(&new, NULL);
>- if (new.tv_sec - last.tv_sec > WAIT_TIME) {
>- ERRMSG("Can't get data of pfn %llx.\n", consuming_pfn);
>- goto out;
>- }
>+ /*
>+ * ready == 0 means the page_flag_buf haven't been used.
>+ * So we will skip it.
>+ */
>+ if (info->page_flag_buf[i]->ready == 0)
>+ continue;
>+ temp_pfn = info->page_flag_buf[i]->pfn;
>
>- /*
>- * check pfn first without mutex locked to reduce the time
>- * trying to lock the mutex
>- */
>- if (page_data_buf[index].pfn != consuming_pfn)
>- continue;
>+ /*
>+ * count how many threads have reached the end.
>+ */
>+ if (temp_pfn >= end_pfn) {
>+ end_count++;
>+ continue;
>+ }
>
>- if (pthread_mutex_trylock(&page_data_buf[index].mutex) != 0)
>- continue;
>+ if (current_pfn < temp_pfn)
>+ continue;
>
>- /* check whether the found one is ready to be consumed */
>- if (page_data_buf[index].pfn != consuming_pfn ||
>- page_data_buf[index].ready != 1) {
>- goto unlock;
>+ check_count++;
>+ consuming = i;
>+ current_pfn = temp_pfn;
>+ }
>+
>+ /*
>+ * If all the threads have reached the end, we will finish writing.
>+ */
>+ if (end_count >= info->num_threads)
>+ goto finish;
>+
>+ /*
>+ * Since it has the probabilty that there is no page_flag_buf being ready,
>+ * we should recheck if it happens.
>+ */
>+ if (check_count == 0)
>+ continue;
>+
>+ /*
>+ * When we check the pfn in page_flag_buf, it may be being produced.
>+ * So we should wait until it is ready to use. And if the pfn is
>+ * different from the value when we check, we should rechoose the buf.
>+ */
>+ gettimeofday(&last, NULL);
>+ while (info->page_flag_buf[consuming]->ready != 1) {
>+ gettimeofday(&new, NULL);
>+ if (new.tv_sec - last.tv_sec > WAIT_TIME) {
>+ ERRMSG("Can't get data of pfn.\n");
>+ goto out;
>+ }
>+ }
>+
>+ if (current_pfn == info->page_flag_buf[consuming]->pfn)
>+ break;
> }
>
> if ((num_dumped % per) == 0)
> print_progress(PROGRESS_COPY, num_dumped, info->num_dumpable);
>
>- /* next pfn is found, refresh last here */
>- last = new;
>- consuming_pfn++;
>- info->consumed_pfn++;
>- page_data_buf[index].ready = 0;
>-
>- if (page_data_buf[index].dumpable == FALSE)
>- goto unlock;
>-
> num_dumped++;
>
>- if (page_data_buf[index].zero == TRUE) {
>+
>+ if (info->page_flag_buf[consuming]->zero == TRUE) {
> if (!write_cache(cd_header, pd_zero, sizeof(page_desc_t)))
> goto out;
> pfn_zero++;
> } else {
>+ index = info->page_flag_buf[consuming]->index;
> pd.flags = page_data_buf[index].flags;
> pd.size = page_data_buf[index].size;
> pd.page_flags = 0;
>@@ -7420,12 +7515,12 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> */
> if (!write_cache(cd_page, page_data_buf[index].buf, pd.size))
> goto out;
>-
>+ page_data_buf[index].used = 0;
> }
>-unlock:
>- pthread_mutex_unlock(&page_data_buf[index].mutex);
>+ info->page_flag_buf[consuming]->ready = 0;
>+ info->page_flag_buf[consuming] = info->page_flag_buf[consuming]->next;
>
> }
>-
>+finish:
> ret = TRUE;
> /*
> * print [100 %]
>@@ -7464,7 +7559,7 @@ out:
> }
>
> if (page_data_buf != NULL) {
>- for (i = 0; i < page_data_num; i++) {
>+ for (i = 0; i < page_buf_num; i++) {
> pthread_mutex_destroy(&page_data_buf[i].mutex);
> }
> }
>@@ -7564,6 +7659,7 @@ write_kdump_pages_cyclic(struct cache_data *cd_header, struct cache_data *cd_pag
> num_dumped++;
> if (!read_pfn(pfn, buf))
> goto out;
>+
> filter_data_buffer(buf, pfn_to_paddr(pfn), info->page_size);
>
> /*
>diff --git a/makedumpfile.h b/makedumpfile.h
>index e0b5bbf..7452e24 100644
>--- a/makedumpfile.h
>+++ b/makedumpfile.h
>@@ -977,7 +977,7 @@ typedef unsigned long long int ulonglong;
> #define PAGE_DATA_NUM (50)
> #define WAIT_TIME (60 * 10)
> #define PTHREAD_FAIL ((void *)-2)
>-#define NUM_BUFFERS (50)
>+#define NUM_BUFFERS (20)
>
> struct mmap_cache {
> char *mmap_buf;
>@@ -985,28 +985,31 @@ struct mmap_cache {
> off_t mmap_end_offset;
> };
>
>+struct page_flag {
>+ mdf_pfn_t pfn;
>+ char zero;
>+ char ready;
>+ short index;
>+ struct page_flag *next;
>+};
>+
> struct page_data
> {
>- mdf_pfn_t pfn;
>- int dumpable;
>- int zero;
>- unsigned int flags;
>+ pthread_mutex_t mutex;
> long size;
> unsigned char *buf;
>- pthread_mutex_t mutex;
>- /*
>- * whether the page_data is ready to be consumed
>- */
>- int ready;
>+ int flags;
>+ int used;
> };
>
> struct thread_args {
> int thread_num;
> unsigned long len_buf_out;
> mdf_pfn_t start_pfn, end_pfn;
>- int page_data_num;
>+ int page_buf_num;
> struct cycle *cycle;
> struct page_data *page_data_buf;
>+ struct page_flag *page_flag_buf;
> };
>
> /*
>@@ -1295,6 +1298,7 @@ struct DumpInfo {
> pthread_t **threads;
> struct thread_args *kdump_thread_args;
> struct page_data *page_data_buf;
>+ struct page_flag **page_flag_buf;
> pthread_rwlock_t usemmap_rwlock;
> mdf_pfn_t current_pfn;
> pthread_mutex_t current_pfn_mutex;
>--
>1.8.3.1
>
>
>
>
>_______________________________________________
>kexec mailing list
>kexec@lists.infradead.org
>http://lists.infradead.org/mailman/listinfo/kexec
_______________________________________________
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kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2016-01-22 5:02 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-01-18 2:00 [PATCH RFC] Improve the performance of --num-threads -d 31 Zhou Wenjian
2016-01-18 5:09 ` "Zhou, Wenjian/周文剑"
2016-01-22 4:53 ` Atsushi Kumagai
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