[PATCH 17/21] perf: Carve out mmap helpers for general use

Borislav Petkov
2010-07-01T15:56:12Z

Export the mmap_read* helpers into tools/lib/perf/mmap.[ch]

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
tools/lib/Makefile | 2 +
tools/lib/perf/mmap.c | 97 +++++++++++++++++++++++++++++++++++++
tools/lib/perf/mmap.h | 15 ++++++
tools/perf/builtin-record.c | 113 +++++--------------------------------------
tools/perf/builtin-top.c | 21 +-------
5 files changed, 129 insertions(+), 119 deletions(-)
create mode 100644 tools/lib/perf/mmap.c
create mode 100644 tools/lib/perf/mmap.h

diff --git a/tools/lib/Makefile b/tools/lib/Makefile
index 780c4fc..6f7102b 100644
--- a/tools/lib/Makefile
+++ b/tools/lib/Makefile
@@ -13,6 +13,7 @@ LIB_H += lk/strbuf.h
LIB_H += lk/color.h
LIB_H += lk/debug.h
LIB_H += lk/strlist.h
+LIB_H += perf/mmap.h
LIB_H += perf/parse-events.h
LIB_H += perf/header.h
LIB_H += perf/symbol.h
@@ -40,6 +41,7 @@ LIB_OBJS += $(OUTPUT)lk/debug.o
LIB_OBJS += $(OUTPUT)lk/string.o
LIB_OBJS += $(OUTPUT)lk/rbtree.o
LIB_OBJS += $(OUTPUT)lk/strlist.o
+LIB_OBJS += $(OUTPUT)perf/mmap.o
LIB_OBJS += $(OUTPUT)perf/parse-events.o
LIB_OBJS += $(OUTPUT)perf/header.o
LIB_OBJS += $(OUTPUT)perf/symbol.o
diff --git a/tools/lib/perf/mmap.c b/tools/lib/perf/mmap.c
new file mode 100644
index 0000000..02befbd
--- /dev/null
+++ b/tools/lib/perf/mmap.c
@@ -0,0 +1,97 @@
+#include <perf.h>
+#include <lk/util.h>
+#include "mmap.h"
+
+unsigned long mmap_read_head(struct mmap_data *md)
+{
+ struct perf_event_mmap_page *pc = md->base;
+ long head;
+
+ head = pc->data_head;
+ rmb();
+
+ return head;
+}
+
+static void mmap_write_tail(struct mmap_data *md, unsigned long tail)
+{
+ struct perf_event_mmap_page *pc = md->base;
+
+ /*
+ * ensure all reads are done before we write the tail out.
+ */
+ /* mb(); */
+ pc->data_tail = tail;
+}
+
+static unsigned long mmap_read(struct mmap_data *md,
+ void (*write_output)(void *, size_t))
+{
+ unsigned int head = mmap_read_head(md);
+ unsigned int old = md->prev;
+ unsigned int page_size;
+ unsigned char *data;
+ unsigned long size, samples = 0;
+ void *buf;
+ int diff;
+
+ page_size = sysconf(_SC_PAGE_SIZE);
+ data = md->base + page_size;
+
+ /*
+ * If we're further behind than half the buffer, there's a chance
+ * the writer will bite our tail and mess up the samples under us.
+ *
+ * If we somehow ended up ahead of the head, we got messed up.
+ *
+ * In either case, truncate and restart at head.
+ */
+ diff = head - old;
+ if (diff < 0) {
+ warning("failed to keep up with mmap data\n");
+ /*
+ * head points to a known good entry, start there.
+ */
+ old = head;
+ }
+
+ if (old != head)
+ samples++;
+
+ size = head - old;
+
+ if ((old & md->mask) + size != (head & md->mask)) {
+ buf = &data[old & md->mask];
+ size = md->mask + 1 - (old & md->mask);
+ old += size;
+
+ write_output(buf, size);
+ }
+
+ buf = &data[old & md->mask];
+ size = head - old;
+ old += size;
+
+ write_output(buf, size);
+
+ md->prev = old;
+ mmap_write_tail(md, old);
+
+ return samples;
+}
+
+
+unsigned long mmap_read_all(struct mmap_data *mmap_array, int nr_cpus,
+ void (*write_output)(void *, size_t))
+{
+ int i;
+ unsigned long samples = 0;
+
+ for (i = 0; i < nr_cpus; i++) {
+ if (mmap_array[i].base)
+ samples += mmap_read(&mmap_array[i], write_output);
+ }
+
+ return samples;
+
+}
diff --git a/tools/lib/perf/mmap.h b/tools/lib/perf/mmap.h
new file mode 100644
index 0000000..b6622e5
--- /dev/null
+++ b/tools/lib/perf/mmap.h
@@ -0,0 +1,15 @@
+#ifndef __PERF_MMAP_H
+#define __PERF_MMAP_H
+
+struct mmap_data {
+ int counter;
+ void *base;
+ unsigned int mask;
+ unsigned int prev;
+};
+
+unsigned long mmap_read_head(struct mmap_data *md);
+unsigned long mmap_read_all(struct mmap_data *, int,
+ void (*write_output)(void *, size_t));
+
+#endif /* __PERF_MMAP_H */
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 241c334..cb33e71 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -8,19 +8,19 @@
#define _FILE_OFFSET_BITS 64

#include "builtin.h"
-
#include "perf.h"

#include <lk/util.h>
-#include <lk/cpumap.h>
#include <lk/debug.h>
+#include <lk/cpumap.h>
#include <perf/misc.h>
-#include <perf/parse-events.h>
-#include <perf/build-id.h>
-#include <perf/header.h>
+#include <perf/mmap.h>
#include <perf/event.h>
-#include <perf/session.h>
+#include <perf/header.h>
#include <perf/symbol.h>
+#include <perf/session.h>
+#include <perf/build-id.h>
+#include <perf/parse-events.h>

#include "util/parse-options.h"

@@ -63,7 +63,7 @@ static bool no_samples = false;
static bool sample_address = false;
static bool no_buildid = false;

-static long samples = 0;
+static unsigned long samples = 0;
static u64 bytes_written = 0;

static struct pollfd *event_array;
@@ -77,37 +77,8 @@ static off_t post_processing_offset;
static struct perf_session *session;
static const char *cpu_list;

-struct mmap_data {
- int counter;
- void *base;
- unsigned int mask;
- unsigned int prev;
-};
-
static struct mmap_data mmap_array[MAX_NR_CPUS];

-static unsigned long mmap_read_head(struct mmap_data *md)
-{
- struct perf_event_mmap_page *pc = md->base;
- long head;
-
- head = pc->data_head;
- rmb();
-
- return head;
-}
-
-static void mmap_write_tail(struct mmap_data *md, unsigned long tail)
-{
- struct perf_event_mmap_page *pc = md->base;
-
- /*
- * ensure all reads are done before we write the tail out.
- */
- /* mb(); */
- pc->data_tail = tail;
-}
-
static void advance_output(size_t size)
{
bytes_written += size;
@@ -135,55 +106,6 @@ static int process_synthesized_event(event_t *event,
return 0;
}

-static void mmap_read(struct mmap_data *md)
-{
- unsigned int head = mmap_read_head(md);
- unsigned int old = md->prev;
- unsigned char *data = md->base + page_size;
- unsigned long size;
- void *buf;
- int diff;
-
- /*
- * If we're further behind than half the buffer, there's a chance
- * the writer will bite our tail and mess up the samples under us.
- *
- * If we somehow ended up ahead of the head, we got messed up.
- *
- * In either case, truncate and restart at head.
- */
- diff = head - old;
- if (diff < 0) {
- fprintf(stderr, "WARNING: failed to keep up with mmap data\n");
- /*
- * head points to a known good entry, start there.
- */
- old = head;
- }
-
- if (old != head)
- samples++;
-
- size = head - old;
-
- if ((old & md->mask) + size != (head & md->mask)) {
- buf = &data[old & md->mask];
- size = md->mask + 1 - (old & md->mask);
- old += size;
-
- write_output(buf, size);
- }
-
- buf = &data[old & md->mask];
- size = head - old;
- old += size;
-
- write_output(buf, size);
-
- md->prev = old;
- mmap_write_tail(md, old);
-}
-
static volatile int done = 0;
static volatile int signr = -1;

@@ -493,19 +415,6 @@ static struct perf_event_header finished_round_event = {
.type = PERF_RECORD_FINISHED_ROUND,
};

-static void mmap_read_all(void)
-{
- int i;
-
- for (i = 0; i < nr_cpu; i++) {
- if (mmap_array[i].base)
- mmap_read(&mmap_array[i]);
- }
-
- if (perf_header__has_feat(&session->header, HEADER_TRACE_INFO))
- write_output(&finished_round_event, sizeof(finished_round_event));
-}
-
static int __cmd_record(int argc, const char **argv)
{
int i, counter;
@@ -739,10 +648,14 @@ static int __cmd_record(int argc, const char **argv)
close(go_pipe[1]);

for (;;) {
- int hits = samples;
+ unsigned long hits = samples;
int thread;

- mmap_read_all();
+ samples = mmap_read_all(mmap_array, nr_cpu, write_output);
+
+ if (perf_header__has_feat(&session->header, HEADER_TRACE_INFO))
+ write_output(&finished_round_event,
+ sizeof(finished_round_event));

if (hits == samples) {
if (done)
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 866ba3d..1522ca0 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -28,6 +28,7 @@
#include <linux/rbtree.h>
#include "util/parse-options.h"
#include <perf/parse-events.h>
+#include <perf/mmap.h>
#include <lk/cpumap.h>

#include <lk/debug.h>
@@ -1102,24 +1103,6 @@ static int event__process(event_t *event, struct perf_session *session)
return 0;
}

-struct mmap_data {
- int counter;
- void *base;
- int mask;
- unsigned int prev;
-};
-
-static unsigned int mmap_read_head(struct mmap_data *md)
-{
- struct perf_event_mmap_page *pc = md->base;
- int head;
-
- head = pc->data_head;
- rmb();
-
- return head;
-}
-
static void perf_session__mmap_read_counter(struct perf_session *self,
struct mmap_data *md)
{
@@ -1137,7 +1120,7 @@ static void perf_session__mmap_read_counter(struct perf_session *self,
* In either case, truncate and restart at head.
*/
diff = head - old;
- if (diff > md->mask / 2 || diff < 0) {
+ if ((unsigned)diff > md->mask / 2 || diff < 0) {
fprintf(stderr, "WARNING: failed to keep up with mmap data.\n");

/*
--
1.7.1