[PATCH 09/20] perf: Carve out mmap helpers for general use

Borislav Petkov
2010-11-04T15:39:28Z

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

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
tools/Makefile | 6 ++-
tools/lib/perf/Makefile | 35 ++++++++++++++
tools/lib/perf/mmap.c | 95 ++++++++++++++++++++++++++++++++++++++
tools/lib/perf/mmap.h | 15 ++++++
tools/perf/Makefile | 2 +-
tools/perf/builtin-record.c | 107 ++++---------------------------------------
tools/perf/builtin-top.c | 28 ++---------
7 files changed, 166 insertions(+), 122 deletions(-)
create mode 100644 tools/lib/perf/Makefile
create mode 100644 tools/lib/perf/mmap.c
create mode 100644 tools/lib/perf/mmap.h

diff --git a/tools/Makefile b/tools/Makefile
index d3b1447..691f78b 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -34,7 +34,7 @@ export BASIC_CFLAGS
PERF_TOP_DIR := $(CURDIR)
export PERF_TOP_DIR

-perf: libparsevent lklib .FORCE
+perf: libparsevent lklib lkperflib .FORCE
$(QUIET_SUBDIR0)perf/ $(QUIET_SUBDIR1)

libparsevent: .FORCE
@@ -43,9 +43,13 @@ libparsevent: .FORCE
lklib: .FORCE
$(QUIET_SUBDIR0)lib/lk/ $(QUIET_SUBDIR1)

+lkperflib: .FORCE
+ $(QUIET_SUBDIR0)lib/perf/ $(QUIET_SUBDIR1)
+
clean:
$(QUIET_SUBDIR0)lib/trace/ $(QUIET_SUBDIR1) clean
$(QUIET_SUBDIR0)lib/lk/ $(QUIET_SUBDIR1) clean
+ $(QUIET_SUBDIR0)lib/perf/ $(QUIET_SUBDIR1) clean
$(QUIET_SUBDIR0)perf/ $(QUIET_SUBDIR1) clean

.PHONY: clean .FORCE
diff --git a/tools/lib/perf/Makefile b/tools/lib/perf/Makefile
new file mode 100644
index 0000000..9942d52
--- /dev/null
+++ b/tools/lib/perf/Makefile
@@ -0,0 +1,35 @@
+include ../../scripts/Makefile.lib
+
+# guard against environment variables
+LIB_H=
+LIB_OBJS=
+
+LIB_H += mmap.h
+
+LIB_OBJS += mmap.o
+
+LIBFILE = $(LIB_OUTPUT)lkperflib.a
+
+CFLAGS = -ggdb3 -Wall -Wextra -std=gnu99 -Werror $(CFLAGS_OPTIMIZE) -D_FORTIFY_SOURCE=2 $(EXTRA_WARNINGS) $(EXTRA_CFLAGS)
+EXTLIBS = -lpthread -lrt -lelf -lm
+ALL_CFLAGS = $(CFLAGS) $(BASIC_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64
+ALL_LDFLAGS = $(LDFLAGS)
+
+RM = rm -f
+
+$(LIBFILE): $(LIB_OBJS)
+ $(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(LIB_OBJS)
+
+$(LIB_OBJS): $(LIB_H)
+
+%.o: %.c
+ $(QUIET_CC)$(CC) -o $@ -c $(ALL_CFLAGS) $<
+%.s: %.c
+ $(QUIET_CC)$(CC) -S $(ALL_CFLAGS) $<
+%.o: %.S
+ $(QUIET_CC)$(CC) -o $@ -c $(ALL_CFLAGS) $<
+
+clean:
+ $(RM) $(LIB_OBJS) $(LIBFILE)
+
+.PHONY: clean
diff --git a/tools/lib/perf/mmap.c b/tools/lib/perf/mmap.c
new file mode 100644
index 0000000..b154ccc
--- /dev/null
+++ b/tools/lib/perf/mmap.c
@@ -0,0 +1,95 @@
+#include <stdio.h>
+#include <perf.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) {
+ 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);
+
+ 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/Makefile b/tools/perf/Makefile
index 49690b8..e8c1ada 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -328,7 +328,7 @@ export PERL_PATH

LIB_FILE=$(OUTPUT)libperf.a

-EXTRA_LIB_FILES=$(LIB_OUTPUT)libparsevent.a $(LIB_OUTPUT)lklib.a
+EXTRA_LIB_FILES=$(LIB_OUTPUT)libparsevent.a $(LIB_OUTPUT)lklib.a $(LIB_OUTPUT)lkperflib.a

LIB_H += ../../include/linux/perf_event.h
LIB_H += ../../include/linux/rbtree.h
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 1fa7a06..99a71c5 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -6,22 +6,21 @@
* later analysis via perf report.
*/
#define _FILE_OFFSET_BITS 64
-
#include "builtin.h"
-
#include "perf.h"

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

#include <unistd.h>
#include <sched.h>
@@ -62,7 +61,7 @@ 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;
@@ -76,37 +75,8 @@ 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;
@@ -134,55 +104,6 @@ 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;

@@ -485,19 +406,6 @@ 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;
@@ -734,10 +642,13 @@ 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 b5bc157..773676f 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -24,11 +24,8 @@
#include "util/session.h"
#include "util/symbol.h"
#include "util/thread.h"
-#include <lk/util.h>
-#include <linux/rbtree.h>
#include "util/parse-options.h"
#include "util/parse-events.h"
-#include <lk/cpumap.h>

#include "util/debug.h"

@@ -52,6 +49,11 @@
#include <sys/uio.h>
#include <sys/mman.h>

+#include <lk/util.h>
+#include <lk/cpumap.h>
+#include <perf/mmap.h>
+
+#include <linux/rbtree.h>
#include <linux/unistd.h>
#include <linux/types.h>

@@ -1082,24 +1084,6 @@ static void event__process_sample(const event_t *self,
}
}

-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)
{
@@ -1117,7 +1101,7 @@ 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");

/*
--
1.7.3.1