kernel.git/tools/perf/util/event.c, branch linux-4.4.y

perf tools: Make perf_event__synthesize_mmap_events() scale

2018-03-22T08:23:20Z

[ Upstream commit 88b897a30c525c2eee6e7f16e1e8d0f18830845e ] This patch significantly improves the execution time of perf_event__synthesize_mmap_events() when running perf record on systems where processes have lots of threads. It just happens that cat /proc/pid/maps support uses a O(N^2) algorithm to generate each map line in the maps file. If you have 1000 threads, then you have necessarily 1000 stacks. For each vma, you need to check if it corresponds to a thread's stack. With a large number of threads, this can take a very long time. I have seen latencies >> 10mn. As of today, perf does not use the fact that a mapping is a stack, therefore we can work around the issue by using /proc/pid/tasks/pid/maps. This entry does not try to map a vma to stack and is thus much faster with no loss of functonality. The proc-map-timeout logic is kept in case users still want some upper limit. In V2, we fix the file path from /proc/pid/tasks/pid/maps to actual /proc/pid/task/pid/maps, tasks -> task. Thanks Arnaldo for catching this. Committer note: This problem seems to have been elliminated in the kernel since commit : b18cb64ead40 ("fs/proc: Stop trying to report thread stacks"). Signed-off-by: Stephane Eranian Acked-by: Jiri Olsa Cc: Andy Lutomirski Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20170315135059.GC2177@redhat.com Link: http://lkml.kernel.org/r/1489598233-25586-1-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

perf tools: Use readdir() instead of deprecated readdir_r()

2017-07-15T09:57:48Z

commit 7093b4c963cc4e344e490c774924a180602a7092 upstream. The readdir() function is thread safe as long as just one thread uses a DIR, which is the case when synthesizing events for pre-existing threads by traversing /proc, so, to avoid breaking the build with glibc-2.23.90 (upcoming 2.24), use it instead of readdir_r(). See: http://man7.org/linux/man-pages/man3/readdir.3.html "However, in modern implementations (including the glibc implementation), concurrent calls to readdir() that specify different directory streams are thread-safe. In cases where multiple threads must read from the same directory stream, using readdir() with external synchronization is still preferable to the use of the deprecated readdir_r(3) function." Noticed while building on a Fedora Rawhide docker container. CC /tmp/build/perf/util/event.o util/event.c: In function '__event__synthesize_thread': util/event.c:466:2: error: 'readdir_r' is deprecated [-Werror=deprecated-declarations] while (!readdir_r(tasks, &dirent, &next) && next) { ^~~~~ In file included from /usr/include/features.h:368:0, from /usr/include/stdint.h:25, from /usr/lib/gcc/x86_64-redhat-linux/6.0.0/include/stdint.h:9, from /git/linux/tools/include/linux/types.h:6, from util/event.c:1: /usr/include/dirent.h:189:12: note: declared here Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-i1vj7nyjp2p750rirxgrfd3c@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf tools: handle spaces in file names obtained from /proc/pid/maps

2016-05-04T21:48:53Z

commit 89fee59b504f86925894fcc9ba79d5c933842f93 upstream. Steam frequently puts game binaries in folders with spaces. Note: "(deleted)" markers are now treated as part of the file name. Signed-off-by: Marcin Ślusarz Acked-by: Namhyung Kim Fixes: 6064803313ba ("perf tools: Use sscanf for parsing /proc/pid/maps") Link: http://lkml.kernel.org/r/20160119190303.GA17579@marcin-Inspiron-7720 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf tools: Fix handling read result using a signed variable

2015-10-06T21:04:59Z

The function can return negative value, assigning it to unsigned variable can cause memory corruption. The problem has been detected using proposed semantic patch scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1]. [1]: http://permalink.gmane.org/gmane.linux.kernel/2038576 Signed-off-by: Andrzej Hajda Cc: Bartlomiej Zolnierkiewicz Cc: Marek Szyprowski Cc: Peter Zijlstra Cc: kernel-janitors@vger.kernel.org Link: http://lkml.kernel.org/r/1444122017-16856-1-git-send-email-a.hajda@samsung.com Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Add method for common kernel_map(FUNCTION) operation

2015-09-30T21:34:29Z

And it is also a step in the direction of killing the separation of data and text maps in map_groups. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-rrds86kb3wx5wk8v38v56gw8@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Use machine__kernel_map() thoroughly

2015-09-30T21:34:28Z

In places where we were using its open coded equivalent. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-khkdugcdoqy3tkszm3jdxgbe@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Use mapis_kernel() when synthesizing kernel module mmap records

2015-09-28T18:50:54Z

Equivalent and removes one more case of using dso->kernel. # perf record -a usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.768 MB perf.data (30 samples) ] Before: [root@zoo ~]# perf script --show-task --show-mmap | head -3 swapper 0 [0] 0.0: PERF_RECORD_MMAP -1/0: [0xffffffff81000000(0x1f000000) @ 0xffffffff81000000]: x [kernel.kallsyms]_text swapper 0 [0] 0.0: PERF_RECORD_MMAP -1/0: [0xffffffffa0000000(0xa000) @ 0]: x /lib/modules/4.3.0-rc1+/kernel/drivers/acpi/video.ko swapper 0 [0] 0.0: PERF_RECORD_MMAP -1/0: [0xffffffffa000a000(0x5000) @ 0]: x /lib/modules/4.3.0-rc1+/kernel/drivers/i2c/algos/i2c-algo-bit.ko # # perf script --show-task --show-mmap | head -3 swapper 0 [0] 0.0: PERF_RECORD_MMAP -1/0: [0xffffffff81000000(0x1f000000) @ 0xffffffff81000000]: x [kernel.kallsyms]_text swapper 0 [0] 0.0: PERF_RECORD_MMAP -1/0: [0xffffffffa0000000(0xa000) @ 0]: x /lib/modules/4.3.0-rc1+/kernel/drivers/acpi/video.ko swapper 0 [0] 0.0: PERF_RECORD_MMAP -1/0: [0xffffffffa000a000(0x5000) @ 0]: x /lib/modules/4.3.0-rc1+/kernel/drivers/i2c/algos/i2c-algo-bit.ko # Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Namhyung Kim Cc: Stephane Eranian Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-b65xe578dwq22mzmmj5y94wr@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf record: Synthesize COMM event for a command line workload

2015-09-23T01:43:12Z

When perf creates a new child to profile, the events are enabled on exec(). And in this case, it doesn't synthesize any event for the child since they'll be generated during exec(). But there's an window between the enabling and the event generation. It used to be overcome since samples are only in kernel (so we always have the map) and the comm is overridden by a later COMM event. However it won't work if events are processed and displayed before the COMM event overrides like in 'perf script'. This leads to those early samples (like native_write_msr_safe) not having a comm but pid (like ':15328'). So it needs to synthesize COMM event for the child explicitly before enabling so that it can have a correct comm. But at this time, the comm will be "perf" since it's not exec-ed yet. Committer note: Before this patch: # perf record usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.017 MB perf.data (7 samples) ] # perf script --show-task-events :4429 4429 27909.079372: 1 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4. :4429 4429 27909.079375: 1 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4. :4429 4429 27909.079376: 10 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4. :4429 4429 27909.079377: 223 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4. :4429 4429 27909.079378: 6571 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4. usleep 4429 27909.079380: PERF_RECORD_COMM exec: usleep:4429/4429 usleep 4429 27909.079381: 185403 cycles: ffffffff810a72d3 flush_signal_handlers (/lib/modules/4. usleep 4429 27909.079444: 2241110 cycles: 7fc575355be3 _dl_start (/usr/lib64/ld-2.20.so) usleep 4429 27909.079875: PERF_RECORD_EXIT(4429:4429):(4429:4429) After: # perf record usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.017 MB perf.data (7 samples) ] # perf script --show-task perf 0 0.000000: PERF_RECORD_COMM: perf:8446/8446 perf 8446 30154.038944: 1 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4. perf 8446 30154.038948: 1 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4. perf 8446 30154.038949: 9 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4. perf 8446 30154.038950: 230 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4. perf 8446 30154.038951: 6772 cycles: ffffffff8105f45a native_write_msr_safe (/lib/modules/4. usleep 8446 30154.038952: PERF_RECORD_COMM exec: usleep:8446/8446 usleep 8446 30154.038954: 196923 cycles: ffffffff81766440 _raw_spin_lock (/lib/modules/4.3.0-rc1 usleep 8446 30154.039021: 2292130 cycles: 7f609a173dc4 memcpy (/usr/lib64/ld-2.20.so) usleep 8446 30154.039349: PERF_RECORD_EXIT(8446:8446):(8446:8446) # Signed-off-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Jiri Olsa Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1442881495-2928-1-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add processor socket info to hist_entry and addr_location

2015-09-14T15:50:29Z

This information will come from perf.data files of from the current system, cached when needed, such as when the 'socket' sort order gets introduced. Signed-off-by: Kan Liang Cc: Adrian Hunter Cc: Andi Kleen Cc: Jiri Olsa Cc: Namhyung Kim Cc: Stephane Eranian Cc: Wang Nan Link: http://lkml.kernel.org/r/1441377946-44429-1-git-send-email-kan.liang@intel.com [ Don't blindly use env->cpu[al.cpu].socket_id & use machine->env, fixes by Jiri & Arnaldo ] Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add new PERF_RECORD_SWITCH event

2015-07-24T01:51:13Z

Support processing of PERF_RECORD_SWITCH events and PERF_RECORD_SWITCH_CPU_WIDE events. There is a single tools callback for them both so that the tool must check the event type before using the extra members in PERF_RECORD_SWITCH_CPU_WIDE. There is still no way to select the events, though. That is added in a subsequest patch. Signed-off-by: Adrian Hunter Acked-by: Peter Zijlstra (Intel) Tested-by: Jiri Olsa Cc: Andi Kleen Cc: Mathieu Poirier Cc: Pawel Moll Cc: Stephane Eranian Link: http://lkml.kernel.org/r/1437471846-26995-3-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo