From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
Wang Nan <wangnan0@huawei.com>, Jiri Olsa <jolsa@redhat.com>,
Kan Liang <kan.liang@intel.com>,
Mengting Zhang <zhangmengting@huawei.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: [PATCH 34/36] perf mmap: Fix perf backward recording
Date: Wed, 6 Dec 2017 11:41:13 -0300 [thread overview]
Message-ID: <20171206144115.15097-35-acme@kernel.org> (raw)
In-Reply-To: <20171206144115.15097-1-acme@kernel.org>
From: Wang Nan <wangnan0@huawei.com>
'perf record' backward recording doesn't work as we expected: it never
overwrites when ring buffer gets full.
Test:
Run a busy python printing task background like this:
while True:
print 123
send SIGUSR2 to perf to capture snapshot, then:
# ./perf record --overwrite -e raw_syscalls:sys_enter -e raw_syscalls:sys_exit --exclude-perf -a --switch-output
[ perf record: dump data: Woken up 1 times ]
[ perf record: Dump perf.data.2017110101520743 ]
[ perf record: dump data: Woken up 1 times ]
[ perf record: Dump perf.data.2017110101521251 ]
[ perf record: dump data: Woken up 1 times ]
[ perf record: Dump perf.data.2017110101521692 ]
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Dump perf.data.2017110101521936 ]
[ perf record: Captured and wrote 0.826 MB perf.data.<timestamp> ]
# ./perf script -i ./perf.data.2017110101520743 | head -n3
perf 2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 2400, 0, 59, 100, 0)
perf 2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 (4112340, 2, ffffffff, 3df, 100, 0)
python 2545 [000] 12449.310800: raw_syscalls:sys_exit: NR 1 = 4
# ./perf script -i ./perf.data.2017110101521251 | head -n3
perf 2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 2400, 0, 59, 100, 0)
perf 2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 (4112340, 2, ffffffff, 3df, 100, 0)
python 2545 [000] 12449.310800: raw_syscalls:sys_exit: NR 1 = 4
# ./perf script -i ./perf.data.2017110101521692 | head -n3
perf 2717 [000] 12449.310785: raw_syscalls:sys_enter: NR 16 (5, 2400, 0, 59, 100, 0)
perf 2717 [000] 12449.310790: raw_syscalls:sys_enter: NR 7 (4112340, 2, ffffffff, 3df, 100, 0)
python 2545 [000] 12449.310800: raw_syscalls:sys_exit: NR 1 = 4
Timestamps never change, but my background task is a dead loop, can
easily overwhelm the ring buffer.
This patch fixes it by forcing unsetting PROT_WRITE for a backward ring
buffer, so all backward ring buffers become overwrite ring buffers.
Test result:
# ./perf record --overwrite -e raw_syscalls:sys_enter -e raw_syscalls:sys_exit --exclude-perf -a --switch-output
[ perf record: dump data: Woken up 1 times ]
[ perf record: Dump perf.data.2017110101285323 ]
[ perf record: dump data: Woken up 1 times ]
[ perf record: Dump perf.data.2017110101290053 ]
[ perf record: dump data: Woken up 1 times ]
[ perf record: Dump perf.data.2017110101290446 ]
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Dump perf.data.2017110101290837 ]
[ perf record: Captured and wrote 0.826 MB perf.data.<timestamp> ]
# ./perf script -i ./perf.data.2017110101285323 | head -n3
python 2545 [000] 11064.268083: raw_syscalls:sys_exit: NR 1 = 4
python 2545 [000] 11064.268084: raw_syscalls:sys_enter: NR 1 (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
python 2545 [000] 11064.268086: raw_syscalls:sys_exit: NR 1 = 4
# ./perf script -i ./perf.data.2017110101290 | head -n3
failed to open ./perf.data.2017110101290: No such file or directory
# ./perf script -i ./perf.data.2017110101290053 | head -n3
python 2545 [000] 11071.564062: raw_syscalls:sys_enter: NR 1 (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
python 2545 [000] 11071.564064: raw_syscalls:sys_exit: NR 1 = 4
python 2545 [000] 11071.564066: raw_syscalls:sys_enter: NR 1 (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
# ./perf script -i ./perf.data.2017110101290 | head -n3
perf.data.2017110101290053 perf.data.2017110101290446 perf.data.2017110101290837
# ./perf script -i ./perf.data.2017110101290446 | head -n3
sshd 1321 [000] 11075.499473: raw_syscalls:sys_exit: NR 14 = 0
sshd 1321 [000] 11075.499474: raw_syscalls:sys_enter: NR 14 (2, 7ffe98899490, 0, 8, 0, 3000)
sshd 1321 [000] 11075.499474: raw_syscalls:sys_exit: NR 14 = 0
# ./perf script -i ./perf.data.2017110101290837 | head -n3
python 2545 [000] 11079.280844: raw_syscalls:sys_exit: NR 1 = 4
python 2545 [000] 11079.280847: raw_syscalls:sys_enter: NR 1 (1, 12cc330, 4, 7fc237280370, 7fc2373d0700, 2c7b0)
python 2545 [000] 11079.280850: raw_syscalls:sys_exit: NR 1 = 4
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Mengting Zhang <zhangmengting@huawei.com>
Link: http://lkml.kernel.org/r/20171204165107.95327-2-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/evlist.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 68c1f9546650..b1cea711232b 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -812,6 +812,7 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
int fd;
int cpu;
+ mp->prot = PROT_READ | PROT_WRITE;
if (evsel->attr.write_backward) {
output = _output_backward;
maps = evlist->backward_mmap;
@@ -824,6 +825,7 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
if (evlist->bkw_mmap_state == BKW_MMAP_NOTREADY)
perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_RUNNING);
}
+ mp->prot &= ~PROT_WRITE;
}
if (evsel->system_wide && thread)
@@ -1058,9 +1060,12 @@ int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
struct perf_evsel *evsel;
const struct cpu_map *cpus = evlist->cpus;
const struct thread_map *threads = evlist->threads;
- struct mmap_params mp = {
- .prot = PROT_READ | PROT_WRITE,
- };
+ /*
+ * Delay setting mp.prot: set it before calling perf_mmap__mmap.
+ * Its value is decided by evsel's write_backward.
+ * So &mp should not be passed through const pointer.
+ */
+ struct mmap_params mp;
if (!evlist->mmap)
evlist->mmap = perf_evlist__alloc_mmap(evlist);
--
2.13.6
next prev parent reply other threads:[~2017-12-06 14:44 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20171206144115.15097-1-acme@kernel.org>
2017-12-06 14:40 ` [PATCH 01/36] tools headers: Follow the upstream UAPI header version 100% differ from the kernel Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 02/36] perf test: Disable test cases 19 and 20 on s390x Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 03/36] perf record: Synthesize unit/scale/... in event update Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 04/36] perf record: Synthesize thread map and cpu map Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 05/36] perf script: Allow computing 'perf stat' style metrics Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 06/36] perf buildid-cache: Document for Node.js USDT Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 07/36] perf report: Fix -D output for user metadata events Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 08/36] perf intel-pt: Improve build messages for files that differ from the kernel Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 09/36] Documentation: Add Arnaldo Melo to list of enforcement statement endorsers Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 10/36] perf bench futex: Use cpumaps Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 11/36] tools build feature: Check if pthread_barrier_t is available Arnaldo Carvalho de Melo
2017-12-06 21:31 ` Philippe Ombredanne
2017-12-07 11:24 ` Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 12/36] perf bench futex: Sync waker threads Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 13/36] perf annotate: Fix unnecessary memory allocation for s390x Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 14/36] perf annotate: Fix objdump comment parsing for Intel mov dissassembly Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 15/36] perf rblist: Create rblist__exit() function Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 16/36] perf stat: Add rbtree node_delete op Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 17/36] perf thread_map: Add method to map all threads in the system Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 18/36] perf s390: Always build with -fPIC Arnaldo Carvalho de Melo
2017-12-07 8:09 ` Hendrik Brueckner
2017-12-28 15:34 ` [tip:perf/core] " tip-bot for Hendrik Brueckner
2017-12-06 14:40 ` [PATCH 19/36] perf pmu: Pass pmu as a parameter to get_cpuid_str() Arnaldo Carvalho de Melo
2017-12-06 14:40 ` [PATCH 20/36] perf tools arm64: Add support for get_cpuid_str function Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 21/36] perf pmu: Add helper function is_pmu_core to detect PMU CORE devices Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 22/36] perf vendor events arm64: Add ThunderX2 implementation defined pmu core events Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 23/36] perf pmu: Add check for valid cpuid in perf_pmu__find_map() Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 24/36] perf tools: Fix up build in hardnened environments Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 25/36] perf evlist: Remove 'overwrite' parameter from perf_evlist__mmap Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 26/36] perf evlist: Remove 'overwrite' parameter from perf_evlist__mmap_ex Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 27/36] perf evlist: Remove evlist->overwrite Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 28/36] perf mmap: Remove overwrite from arguments list of perf_mmap__push Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 29/36] perf mmap: Remove overwrite and check_messup from mmap read Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 30/36] perf c2c: Add a tip about cacheline events Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 31/36] perf vendor events: Use more flexible pattern matching for CPU identification for mapfile.csv Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 32/36] x86/asm: Allow again using asm.h when building for the 'bpf' clang target Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 33/36] perf report: Set browser mode right before setup_browser() Arnaldo Carvalho de Melo
2017-12-06 14:41 ` Arnaldo Carvalho de Melo [this message]
2017-12-06 14:41 ` [PATCH 35/36] perf mmap: Don't discard prev in backward mode Arnaldo Carvalho de Melo
2017-12-06 14:41 ` [PATCH 36/36] perf tools: Rename 'backward' to 'overwrite' in evlist, mmap and record Arnaldo Carvalho de Melo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20171206144115.15097-35-acme@kernel.org \
--to=acme@kernel.org \
--cc=acme@redhat.com \
--cc=jolsa@redhat.com \
--cc=kan.liang@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-perf-users@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=wangnan0@huawei.com \
--cc=zhangmengting@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox