[PATCH v15 1/3]: perf util: map data buffer for preserving collected data

From: Alexey Budankov
Date: Tue Nov 06 2018 - 04:03:42 EST



The map->data buffer is used to preserve map->base profiling data
for writing to disk. AIO map->cblock is used to queue corresponding
map->data buffer for asynchronous writing.

Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
---
Changes in v15:
- implemented libaio feature check and defined HAVE_AIO_SUPPORT accordingly
Changes in v13:
- grouped aio functions under single #ifdef HAVE_AIO_SUPPORT
Changes in v12:
- applied stub functions design for the whole patch kit
- grouped AIO related data into a struct under struct perf_mmap
Changes in v10:
- moved specific code to perf_mmap__aio_mmap(), perf_mmap__aio_munmap()
- adjusted error reporting by using %m
Changes in v9:
- implemented NO_AIO and HAVE_AIO_SUPPORT defines to cover cases of
libc implementations without Posix AIO API support
Changes in v7:
- implemented handling record.aio setting from perfconfig file
Changes in v6:
- adjusted setting of priorities for cblocks;
Changes in v5:
- reshaped layout of data structures;
- implemented --aio option;
Changes in v4:
- converted mmap()/munmap() to malloc()/free() for mmap->data buffer management
Changes in v2:
- converted zalloc() to calloc() for allocation of mmap_aio array,
- cleared typo and adjusted fallback branch code;
---
tools/build/Makefile.feature | 6 +++--
tools/build/feature/Makefile | 6 ++++-
tools/build/feature/test-all.c | 5 ++++
tools/build/feature/test-libaio.c | 16 +++++++++++++
tools/perf/Makefile.config | 6 +++++
tools/perf/Makefile.perf | 7 +++++-
tools/perf/util/evlist.c | 2 +-
tools/perf/util/mmap.c | 49 ++++++++++++++++++++++++++++++++++++++-
tools/perf/util/mmap.h | 11 ++++++++-
9 files changed, 101 insertions(+), 7 deletions(-)

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index f216b2f5c3d7..185b1932b25a 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -68,7 +68,8 @@ FEATURE_TESTS_BASIC := \
sched_getcpu \
sdt \
setns \
- libopencsd
+ libopencsd \
+ libaio

# FEATURE_TESTS_BASIC + FEATURE_TESTS_EXTRA is the complete list
# of all feature tests
@@ -114,7 +115,8 @@ FEATURE_DISPLAY ?= \
zlib \
lzma \
get_cpuid \
- bpf
+ bpf \
+ libaio

# Set FEATURE_CHECK_(C|LD)FLAGS-all for all FEATURE_TESTS features.
# If in the future we need per-feature checks/flags for features not
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 0516259be70f..468817a6bc44 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -58,7 +58,8 @@ FILES= \
test-libopencsd.bin \
test-clang.bin \
test-llvm.bin \
- test-llvm-version.bin
+ test-llvm-version.bin \
+ test-libaio.bin

FILES := $(addprefix $(OUTPUT),$(FILES))

@@ -285,6 +286,9 @@ $(OUTPUT)test-clang.bin:

-include $(OUTPUT)*.d

+$(OUTPUT)test-libaio.bin:
+ $(BUILD) -lrt
+
###############################

clean:
diff --git a/tools/build/feature/test-all.c b/tools/build/feature/test-all.c
index 8dc20a61341f..19ca9c87cc61 100644
--- a/tools/build/feature/test-all.c
+++ b/tools/build/feature/test-all.c
@@ -166,6 +166,10 @@
# include "test-libopencsd.c"
#undef main

+#define main main_test_libaio
+# include "test-libaio.c"
+#undef main
+
int main(int argc, char *argv[])
{
main_test_libpython();
@@ -204,6 +208,7 @@ int main(int argc, char *argv[])
main_test_sdt();
main_test_setns();
main_test_libopencsd();
+ main_test_libaio();

return 0;
}
diff --git a/tools/build/feature/test-libaio.c b/tools/build/feature/test-libaio.c
new file mode 100644
index 000000000000..932133c9a265
--- /dev/null
+++ b/tools/build/feature/test-libaio.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <aio.h>
+
+int main(void)
+{
+ struct aiocb aiocb;
+
+ aiocb.aio_fildes = 0;
+ aiocb.aio_offset = 0;
+ aiocb.aio_buf = 0;
+ aiocb.aio_nbytes = 0;
+ aiocb.aio_reqprio = 0;
+ aiocb.aio_sigevent.sigev_notify = 1 /*SIGEV_NONE*/;
+
+ return (int)aio_return(&aiocb);
+}
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index f6d1a03c7523..533282da45ae 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -357,6 +357,12 @@ ifeq ($(feature-glibc), 1)
CFLAGS += -DHAVE_GLIBC_SUPPORT
endif

+ifeq ($(feature-libaio), 1)
+ ifndef NO_AIO
+ CFLAGS += -DHAVE_AIO_SUPPORT
+ endif
+endif
+
ifdef NO_DWARF
NO_LIBDW_DWARF_UNWIND := 1
endif
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 92514fb3689f..7becc6a72cf2 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -97,8 +97,13 @@ include ../scripts/utilities.mak
# Define LIBCLANGLLVM if you DO want builtin clang and llvm support.
# When selected, pass LLVM_CONFIG=/path/to/llvm-config to `make' if
# llvm-config is not in $PATH.
-
+#
# Define NO_CORESIGHT if you do not want support for CoreSight trace decoding.
+#
+# Define NO_AIO if you do not want support of Posix AIO based trace
+# streaming for record mode. Currently Posix AIO trace streaming is
+# supported only when linking with glibc.
+#

# As per kernel Makefile, avoid funny character set dependencies
unexport LC_ALL
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index be440df29615..1a83bf2c069c 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1028,7 +1028,7 @@ int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
* Its value is decided by evsel's write_backward.
* So &mp should not be passed through const pointer.
*/
- struct mmap_params mp;
+ struct mmap_params mp = { .nr_cblocks = 0 };

if (!evlist->mmap)
evlist->mmap = perf_evlist__alloc_mmap(evlist, false);
diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index cdb95b3a1213..47cdc3ad6546 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -153,8 +153,55 @@ void __weak auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp __mayb
{
}

+#ifdef HAVE_AIO_SUPPORT
+static int perf_mmap__aio_mmap(struct perf_mmap *map, struct mmap_params *mp)
+{
+ int delta_max;
+
+ if (mp->nr_cblocks) {
+ map->aio.data = malloc(perf_mmap__mmap_len(map));
+ if (!map->aio.data) {
+ pr_debug2("failed to allocate data buffer, error %m\n");
+ return -1;
+ }
+ /*
+ * Use cblock.aio_fildes value different from -1
+ * to denote started aio write operation on the
+ * cblock so it requires explicit record__aio_sync()
+ * call prior the cblock may be reused again.
+ */
+ map->aio.cblock.aio_fildes = -1;
+ /*
+ * Allocate cblock with max priority delta to
+ * have faster aio write system calls.
+ */
+ delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX);
+ map->aio.cblock.aio_reqprio = delta_max;
+ }
+
+ return 0;
+}
+
+static void perf_mmap__aio_munmap(struct perf_mmap *map)
+{
+ if (map->aio.data)
+ zfree(&map->aio.data);
+}
+#else
+static int perf_mmap__aio_mmap(struct perf_mmap *map __maybe_unused,
+ struct mmap_params *mp __maybe_unused)
+{
+ return 0;
+}
+
+static void perf_mmap__aio_munmap(struct perf_mmap *map __maybe_unused)
+{
+}
+#endif
+
void perf_mmap__munmap(struct perf_mmap *map)
{
+ perf_mmap__aio_munmap(map);
if (map->base != NULL) {
munmap(map->base, perf_mmap__mmap_len(map));
map->base = NULL;
@@ -197,7 +244,7 @@ int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int c
&mp->auxtrace_mp, map->base, fd))
return -1;

- return 0;
+ return perf_mmap__aio_mmap(map, mp);
}

static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)
diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
index e603314dc792..a46dbdcdcc8a 100644
--- a/tools/perf/util/mmap.h
+++ b/tools/perf/util/mmap.h
@@ -6,6 +6,9 @@
#include <linux/types.h>
#include <asm/barrier.h>
#include <stdbool.h>
+#ifdef HAVE_AIO_SUPPORT
+#include <aio.h>
+#endif
#include "auxtrace.h"
#include "event.h"

@@ -26,6 +29,12 @@ struct perf_mmap {
bool overwrite;
struct auxtrace_mmap auxtrace_mmap;
char event_copy[PERF_SAMPLE_MAX_SIZE] __aligned(8);
+#ifdef HAVE_AIO_SUPPORT
+ struct {
+ void *data;
+ struct aiocb cblock;
+ } aio;
+#endif
};

/*
@@ -57,7 +66,7 @@ enum bkw_mmap_state {
};

struct mmap_params {
- int prot, mask;
+ int prot, mask, nr_cblocks;
struct auxtrace_mmap_params auxtrace_mp;
};