Recent changes (master)

Jens Axboe
2014-07-08T12:00:07Z

The following changes since commit f302710c4b7dd09fa6beb61a983345b2eda2b8d4:

iolog: fix bug when decompressing chunks with different sequence numbers (2014-07-03 21:57:29 -0600)

are available in the git repository at:

git://git.kernel.dk/fio.git master

for you to fetch changes up to 6899b6cb0d996c530e42195cfc29e8e0b02aeae3:

mutex: move pthread_cond_signal() outside of lock (2014-07-08 09:46:37 +0200)

----------------------------------------------------------------
Jens Axboe (3):
Add some new code comments on the log compress/decompress
tp: move pthread_cond_signal() outside of lock
mutex: move pthread_cond_signal() outside of lock

iolog.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++-------------
lib/tp.c | 15 +++++++++++---
mutex.c | 7 ++++++-
3 files changed, 70 insertions(+), 18 deletions(-)

---

Diff of recent changes:

diff --git a/iolog.c b/iolog.c
index 29997ce..5eca53b 100644
--- a/iolog.c
+++ b/iolog.c
@@ -691,6 +691,10 @@ static int z_stream_init(z_stream *stream, int gz_hdr)
stream->opaque = Z_NULL;
stream->next_in = Z_NULL;

+ /*
+ * zlib magic - add 32 for auto-detection of gz header or not,
+ * if we decide to store files in a gzip friendly format.
+ */
if (gz_hdr)
wbits += 32;

@@ -700,7 +704,7 @@ static int z_stream_init(z_stream *stream, int gz_hdr)
return 0;
}

-struct flush_chunk_iter {
+struct inflate_chunk_iter {
unsigned int seq;
void *buf;
size_t buf_size;
@@ -709,7 +713,7 @@ struct flush_chunk_iter {
};

static void finish_chunk(z_stream *stream, FILE *f,
- struct flush_chunk_iter *iter)
+ struct inflate_chunk_iter *iter)
{
int ret;

@@ -723,8 +727,12 @@ static void finish_chunk(z_stream *stream, FILE *f,
iter->buf_size = iter->buf_used = 0;
}

-static size_t flush_chunk(struct iolog_compress *ic, int gz_hdr, FILE *f,
- z_stream *stream, struct flush_chunk_iter *iter)
+/*
+ * Iterative chunk inflation. Handles cases where we cross into a new
+ * sequence, doing flush finish of previous chunk if needed.
+ */
+static size_t inflate_chunk(struct iolog_compress *ic, int gz_hdr, FILE *f,
+ z_stream *stream, struct inflate_chunk_iter *iter)
{
if (ic->seq != iter->seq) {
if (iter->seq)
@@ -770,9 +778,13 @@ static size_t flush_chunk(struct iolog_compress *ic, int gz_hdr, FILE *f,
return (void *) stream->next_in - ic->buf;
}

-static void flush_gz_chunks(struct io_log *log, FILE *f)
+/*
+ * Inflate stored compressed chunks, or write them directly to the log
+ * file if so instructed.
+ */
+static void inflate_gz_chunks(struct io_log *log, FILE *f)
{
- struct flush_chunk_iter iter = { .chunk_sz = log->log_gz, };
+ struct inflate_chunk_iter iter = { .chunk_sz = log->log_gz, };
z_stream stream;

while (!flist_empty(&log->chunk_list)) {
@@ -781,10 +793,14 @@ static void flush_gz_chunks(struct io_log *log, FILE *f)
ic = flist_first_entry(&log->chunk_list, struct iolog_compress, list);
flist_del(&ic->list);

- if (log->log_gz_store)
- fwrite(ic->buf, ic->len, 1, f);
- else
- flush_chunk(ic, log->log_gz_store, f, &stream, &iter);
+ if (log->log_gz_store) {
+ size_t ret;
+
+ ret = fwrite(ic->buf, ic->len, 1, f);
+ if (ret != 1 || ferror(f))
+ log_err("fio: error writing compressed log\n");
+ } else
+ inflate_chunk(ic, log->log_gz_store, f, &stream, &iter);

free_chunk(ic);
}
@@ -795,9 +811,14 @@ static void flush_gz_chunks(struct io_log *log, FILE *f)
}
}

+/*
+ * Open compressed log file and decompress the stored chunks and
+ * write them to stdout. The chunks are stored sequentially in the
+ * file, so we iterate over them and do them one-by-one.
+ */
int iolog_file_inflate(const char *file)
{
- struct flush_chunk_iter iter = { .chunk_sz = 64 * 1024 * 1024, };
+ struct inflate_chunk_iter iter = { .chunk_sz = 64 * 1024 * 1024, };
struct iolog_compress ic;
z_stream stream;
struct stat sb;
@@ -835,11 +856,17 @@ int iolog_file_inflate(const char *file)

fclose(f);

+ /*
+ * Each chunk will return Z_STREAM_END. We don't know how many
+ * chunks are in the file, so we just keep looping and incrementing
+ * the sequence number until we have consumed the whole compressed
+ * file.
+ */
total = ic.len;
do {
size_t ret;

- ret = flush_chunk(&ic, 1, stdout, &stream, &iter);
+ ret = inflate_chunk(&ic, 1, stdout, &stream, &iter);
total -= ret;
if (!total)
break;
@@ -860,7 +887,7 @@ int iolog_file_inflate(const char *file)

#else

-static void flush_gz_chunks(struct io_log *log, FILE *f)
+static void inflate_gz_chunks(struct io_log *log, FILE *f)
{
}

@@ -879,7 +906,7 @@ void flush_log(struct io_log *log)

buf = set_file_buffer(f);

- flush_gz_chunks(log, f);
+ inflate_gz_chunks(log, f);

flush_samples(f, log->log, log->nr_samples * log_entry_sz(log));

@@ -910,6 +937,11 @@ static int finish_log(struct thread_data *td, struct io_log *log, int trylock)

#ifdef CONFIG_ZLIB

+/*
+ * Invoked from our compress helper thread, when logging would have exceeded
+ * the specified memory limitation. Compresses the previously stored
+ * entries.
+ */
static int gz_work(struct tp_work *work)
{
struct iolog_flush_data *data;
@@ -992,6 +1024,12 @@ static int gz_work(struct tp_work *work)
return 0;
}

+/*
+ * Queue work item to compress the existing log entries. We copy the
+ * samples, and reset the log sample count to 0 (so the logging will
+ * continue to use the memory associated with the log). If called with
+ * wait == 1, will not return until the log compression has completed.
+ */
int iolog_flush(struct io_log *log, int wait)
{
struct tp_data *tdat = log->td->tp_data;
diff --git a/lib/tp.c b/lib/tp.c
index 5111910..386e31a 100644
--- a/lib/tp.c
+++ b/lib/tp.c
@@ -1,3 +1,10 @@
+/*
+ * Basic workqueue like code, that sets up a thread and allows async
+ * processing of some sort. Could be extended to allow for multiple
+ * worker threads. But right now fio associates one of this per IO
+ * thread, so should be enough to have just a single thread doing the
+ * work.
+ */
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
@@ -56,8 +63,9 @@ void tp_queue_work(struct tp_data *tdat, struct tp_work *work)

pthread_mutex_lock(&tdat->lock);
flist_add_tail(&work->list, &tdat->work);
- pthread_cond_signal(&tdat->cv);
pthread_mutex_unlock(&tdat->lock);
+
+ pthread_cond_signal(&tdat->cv);
}

void tp_init(struct tp_data **tdatp)
@@ -87,11 +95,12 @@ void tp_exit(struct tp_data **tdatp)
if (!tdat)
return;

- tdat->thread_exit = 1;
pthread_mutex_lock(&tdat->lock);
- pthread_cond_signal(&tdat->cv);
+ tdat->thread_exit = 1;
pthread_mutex_unlock(&tdat->lock);

+ pthread_cond_signal(&tdat->cv);
+
pthread_join(tdat->thread, &ret);

sfree(tdat);
diff --git a/mutex.c b/mutex.c
index 9d10c2c..9ee3bd8 100644
--- a/mutex.c
+++ b/mutex.c
@@ -162,14 +162,19 @@ void fio_mutex_down(struct fio_mutex *mutex)

void fio_mutex_up(struct fio_mutex *mutex)
{
+ int do_wake = 0;
+
assert(mutex->magic == FIO_MUTEX_MAGIC);

pthread_mutex_lock(&mutex->lock);
read_barrier();
if (!mutex->value && mutex->waiters)
- pthread_cond_signal(&mutex->cond);
+ do_wake = 1;
mutex->value++;
pthread_mutex_unlock(&mutex->lock);
+
+ if (do_wake)
+ pthread_cond_signal(&mutex->cond);
}

void fio_rwlock_write(struct fio_rwlock *lock)