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  1. 18 10月, 2018 1 次提交
    • A
      perf tools: Stop fallbacking to kallsyms for vdso symbols lookup · edeb0c90
      由 Arnaldo Carvalho de Melo 提交于 
      David reports that:

<quote>
Perf has this hack where it uses the kernel symbol map as a backup when
a symbol can't be found in the user's symbol table(s).

This causes problems because the tests driving this code path use
machine__kernel_ip(), and that is completely meaningless on Sparc.  On
sparc64 the kernel and user live in physically separate virtual address
spaces, rather than a shared one.  And the kernel lives at a virtual
address that overlaps common userspace addresses.  So this test passes
almost all the time when a user symbol lookup fails.

The consequence of this is that, if the unfound user virtual address in
the sample doesn't match up to a kernel symbol either, we trigger things
like this code in builtin-top.c:

	if (al.sym == NULL && al.map != NULL) {
		const char *msg = "Kernel samples will not be resolved.\n";
		/*
		 * As we do lazy loading of symtabs we only will know if the
		 * specified vmlinux file is invalid when we actually have a
		 * hit in kernel space and then try to load it. So if we get
		 * here and there are _no_ symbols in the DSO backing the
		 * kernel map, bail out.
		 *
		 * We may never get here, for instance, if we use -K/
		 * --hide-kernel-symbols, even if the user specifies an
		 * invalid --vmlinux ;-)
		 */
		if (!machine->kptr_restrict_warned && !top->vmlinux_warned &&
		    __map__is_kernel(al.map) && map__has_symbols(al.map)) {
			if (symbol_conf.vmlinux_name) {
				char serr[256];
				dso__strerror_load(al.map->dso, serr, sizeof(serr));
				ui__warning("The %s file can't be used: %s\n%s",
					    symbol_conf.vmlinux_name, serr, msg);
			} else {
				ui__warning("A vmlinux file was not found.\n%s",
					    msg);
			}

			if (use_browser <= 0)
				sleep(5);
			top->vmlinux_warned = true;
		}
	}

When I fire up a compilation on sparc, this triggers immediately.

I'm trying to figure out what the "backup to kernel map" code is
accomplishing.

I see some language in the current code and in the changes that have
happened in this area talking about vdso.  Does that really happen?

The vdso is mapped into userspace virtual addresses, not kernel ones.

More history.  This didn't cause problems on sparc some time ago,
because the kernel IP check used to be "ip < 0" :-) Sparc kernel
addresses are not negative.  But now with machine__kernel_ip(), which
works using the symbol table determined kernel address range, it does
trigger.

What it all boils down to is that on architectures like sparc,
machine__kernel_ip() should always return false in this scenerio, and
therefore this kind of logic:

		if (cpumode == PERF_RECORD_MISC_USER && machine &&
		    mg != &machine->kmaps &&
		    machine__kernel_ip(machine, al->addr)) {

is basically invalid.  PERF_RECORD_MISC_USER implies no kernel address
can possibly match for the sample/event in question (no matter how
hard you try!) :-)
</>

So, I thought something had changed and in the past we would somehow
find that address in the kallsyms, but I couldn't find anything to back
that up, the patch introducing this is over a decade old, lots of things
changed, so I was just thinking I was missing something.

I tried a gtod busy loop to generate vdso activity and added a 'perf
probe' at that branch, on x86_64 to see if it ever gets hit:

Made thread__find_map() noinline, as 'perf probe' in lines of inline
functions seems to not be working, only at function start. (Masami?)

  # perf probe -x ~/bin/perf -L thread__find_map:57
  <thread__find_map@/home/acme/git/perf/tools/perf/util/event.c:57>
     57                 if (cpumode == PERF_RECORD_MISC_USER && machine &&
     58                     mg != &machine->kmaps &&
     59                     machine__kernel_ip(machine, al->addr)) {
     60                         mg = &machine->kmaps;
     61                         load_map = true;
     62                         goto try_again;
                        }
                } else {
                        /*
                         * Kernel maps might be changed when loading
                         * symbols so loading
                         * must be done prior to using kernel maps.
                         */
     69                 if (load_map)
     70                         map__load(al->map);
     71                 al->addr = al->map->map_ip(al->map, al->addr);

  # perf probe -x ~/bin/perf thread__find_map:60
  Added new event:
    probe_perf:thread__find_map (on thread__find_map:60 in /home/acme/bin/perf)

  You can now use it in all perf tools, such as:

	perf record -e probe_perf:thread__find_map -aR sleep 1

  #

  Then used this to see if, system wide, those probe points were being hit:

  # perf trace -e *perf:thread*/max-stack=8/
  ^C[root@jouet ~]#

  No hits when running 'perf top' and:

  # cat gtod.c
  #include <sys/time.h>

  int main(void)
  {
	struct timeval tv;

	while (1)
		gettimeofday(&tv, 0);

	return 0;
  }
  [root@jouet c]# ./gtod
  ^C

  Pressed 'P' in 'perf top' and the [vdso] samples are there:

  62.84%  [vdso]                    [.] __vdso_gettimeofday
   8.13%  gtod                      [.] main
   7.51%  [vdso]                    [.] 0x0000000000000914
   5.78%  [vdso]                    [.] 0x0000000000000917
   5.43%  gtod                      [.] _init
   2.71%  [vdso]                    [.] 0x000000000000092d
   0.35%  [kernel]                  [k] native_io_delay
   0.33%  libc-2.26.so              [.] __memmove_avx_unaligned_erms
   0.20%  [vdso]                    [.] 0x000000000000091d
   0.17%  [i2c_i801]                [k] i801_access
   0.06%  firefox                   [.] free
   0.06%  libglib-2.0.so.0.5400.3   [.] g_source_iter_next
   0.05%  [vdso]                    [.] 0x0000000000000919
   0.05%  libpthread-2.26.so        [.] __pthread_mutex_lock
   0.05%  libpixman-1.so.0.34.0     [.] 0x000000000006d3a7
   0.04%  [kernel]                  [k] entry_SYSCALL_64_trampoline
   0.04%  libxul.so                 [.] style::dom_apis::query_selector_slow
   0.04%  [kernel]                  [k] module_get_kallsym
   0.04%  firefox                   [.] malloc
   0.04%  [vdso]                    [.] 0x0000000000000910

  I added a 'perf probe' to thread__find_map:69, and that surely got tons
  of hits, i.e. for every map found, just to make sure the 'perf probe'
  command was really working.

  In the process I noticed a bug, we're only have records for '[vdso]' for
  pre-existing commands, i.e. ones that are running when we start 'perf top',
  when we will generate the PERF_RECORD_MMAP by looking at /perf/PID/maps.

  I.e. like this, for preexisting processes with a vdso map, again,
  tracing for all the system, only pre-existing processes get a [vdso] map
  (when having one):

  [root@jouet ~]# perf probe -x ~/bin/perf __machine__addnew_vdso
  Added new event:
  probe_perf:__machine__addnew_vdso (on __machine__addnew_vdso in /home/acme/bin/perf)

  You can now use it in all perf tools, such as:

	perf record -e probe_perf:__machine__addnew_vdso -aR sleep 1

  [root@jouet ~]# perf trace -e probe_perf:__machine__addnew_vdso/max-stack=8/
     0.000 probe_perf:__machine__addnew_vdso:(568eb3)
                                       __machine__addnew_vdso (/home/acme/bin/perf)
                                       map__new (/home/acme/bin/perf)
                                       machine__process_mmap2_event (/home/acme/bin/perf)
                                       machine__process_event (/home/acme/bin/perf)
                                       perf_event__process (/home/acme/bin/perf)
                                       perf_tool__process_synth_event (/home/acme/bin/perf)
                                       perf_event__synthesize_mmap_events (/home/acme/bin/perf)
                                       __event__synthesize_thread (/home/acme/bin/perf)

The kernel is generating a PERF_RECORD_MMAP for vDSOs, but somehow
'perf top' is not getting those records while 'perf record' is:

  # perf record ~acme/c/gtod
  ^C[ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.076 MB perf.data (1499 samples) ]

  # perf report -D | grep PERF_RECORD_MMAP2
  71293612401913 0x11b48 [0x70]: PERF_RECORD_MMAP2 25484/25484: [0x400000(0x1000) @ 0 fd:02 1137 541179306]: r-xp /home/acme/c/gtod
  71293612419012 0x11be0 [0x70]: PERF_RECORD_MMAP2 25484/25484: [0x7fa4a2783000(0x227000) @ 0 fd:00 3146370 854107250]: r-xp /usr/lib64/ld-2.26.so
  71293612432110 0x11c50 [0x60]: PERF_RECORD_MMAP2 25484/25484: [0x7ffcdb53a000(0x2000) @ 0 00:00 0 0]: r-xp [vdso]
  71293612509944 0x11cb0 [0x70]: PERF_RECORD_MMAP2 25484/25484: [0x7fa4a23cd000(0x3b6000) @ 0 fd:00 3149723 262067164]: r-xp /usr/lib64/libc-2.26.so
  #
  # perf script | grep vdso | head
      gtod 25484 71293.612768: 2485554 cycles:ppp:  7ffcdb53a914 [unknown] ([vdso])
      gtod 25484 71293.613576: 2149343 cycles:ppp:  7ffcdb53a917 [unknown] ([vdso])
      gtod 25484 71293.614274: 1814652 cycles:ppp:  7ffcdb53aca8 __vdso_gettimeofday+0x98 ([vdso])
      gtod 25484 71293.614862: 1669070 cycles:ppp:  7ffcdb53acc5 __vdso_gettimeofday+0xb5 ([vdso])
      gtod 25484 71293.615404: 1451589 cycles:ppp:  7ffcdb53acc5 __vdso_gettimeofday+0xb5 ([vdso])
      gtod 25484 71293.615999: 1269941 cycles:ppp:  7ffcdb53ace6 __vdso_gettimeofday+0xd6 ([vdso])
      gtod 25484 71293.616405: 1177946 cycles:ppp:  7ffcdb53a914 [unknown] ([vdso])
      gtod 25484 71293.616775: 1121290 cycles:ppp:  7ffcdb53ac47 __vdso_gettimeofday+0x37 ([vdso])
      gtod 25484 71293.617150: 1037721 cycles:ppp:  7ffcdb53ace6 __vdso_gettimeofday+0xd6 ([vdso])
      gtod 25484 71293.617478:  994526 cycles:ppp:  7ffcdb53ace6 __vdso_gettimeofday+0xd6 ([vdso])
  #

The patch is the obvious one and with it we also continue to resolve
vdso symbols for pre-existing processes in 'perf top' and for all
processes in 'perf record' + 'perf report/script'.
Suggested-by: NDavid Miller <davem@davemloft.net>
Acked-by: NDavid Miller <davem@davemloft.net>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-cs7skq9pp0kjypiju6o7trse@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      edeb0c90
  3. 16 10月, 2018 1 次提交
  5. 09 8月, 2018 1 次提交
    • K
      perf map: Synthesize maps only for thread group leader · e5adfc3e
      由 Konstantin Khlebnikov 提交于 
      Threads share map_groups, all map events are merged into it.

Thus we could send mmaps only for thread group leader.  Otherwise it
took ages to attach and record something from processes with many vmas
and threads.

Thread group leader could be already dead, but it seems perf cannot
handle this case anyway.

Testing dummy:

  #include <stdio.h>
  #include <stdlib.h>
  #include <sys/mman.h>
  #include <pthread.h>
  #include <unistd.h>

  void *thread(void *arg) {
          pause();
  }

  int main(int argc, char **argv) {
        int threads = 10000;
        int vmas = 50000;
        pthread_t th;
        for (int i = 0; i < threads; i++)
                pthread_create(&th, NULL, thread, NULL);
        for (int i = 0; i < vmas; i++)
                mmap(NULL, 4096, (i & 1) ? PROT_READ : PROT_WRITE,
                     MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
        sleep(60);
        return 0;
  }

Comment by Jiri Olsa:

We actualy synthesize the group leader (if we found one) for the thread
even if it's not present in the thread_map, so the process maps are
always in data.
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/153363294102.396323.6277944760215058174.stgit@buzzSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      e5adfc3e
  7. 23 5月, 2018 1 次提交
  9. 22 5月, 2018 1 次提交
  11. 27 4月, 2018 10 次提交
  13. 17 4月, 2018 1 次提交
  15. 17 2月, 2018 2 次提交
  17. 10 1月, 2018 1 次提交
  19. 02 11月, 2017 1 次提交
    • G
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      由 Greg Kroah-Hartman 提交于 
      Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  21. 25 10月, 2017 1 次提交
    • M
      perf report: Use srcline from callchain for hist entries · 1fb7d06a
      由 Milian Wolff 提交于 
      This also removes the symbol name from the srcline column, more on this
below.

This ensures we use the correct srcline, which could originate from a
potentially inlined function. The hist entries used to query for the
srcline based purely on the IP, which leads to wrong results for inlined
entries.

Before:

~~~~~
  perf report --inline -s srcline -g none --stdio
  ...
  # Children      Self  Source:Line
  # ........  ........  ..................................................................................................................................
  #
      94.23%     0.00%  __libc_start_main+18446603487898210537
      94.23%     0.00%  _start+41
      44.58%     0.00%  main+100
      44.58%     0.00%  std::_Norm_helper<true>::_S_do_it<double>+100
      44.58%     0.00%  std::__complex_abs+100
      44.58%     0.00%  std::abs<double>+100
      44.58%     0.00%  std::norm<double>+100
      36.01%     0.00%  hypot+18446603487892193300
      25.81%     0.00%  main+41
      25.81%     0.00%  std::__detail::_Adaptor<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul>, double>::operator()+41
      25.81%     0.00%  std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> >+41
      25.75%    25.75%  random.h:143
      18.39%     0.00%  main+57
      18.39%     0.00%  std::__detail::_Adaptor<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul>, double>::operator()+57
      18.39%     0.00%  std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> >+57
      13.80%    13.80%  random.tcc:3330
       5.64%     0.00%  ??:0
       4.13%     4.13%  __hypot_finite+163
       4.13%     0.00%  __hypot_finite+18446603487892193443
...
~~~~~

After:

~~~~~
  perf report --inline -s srcline -g none --stdio
  ...
  # Children      Self  Source:Line
  # ........  ........  ...........................................
  #
      94.30%     1.19%  main.cpp:39
      94.23%     0.00%  __libc_start_main+18446603487898210537
      94.23%     0.00%  _start+41
      48.44%     1.70%  random.h:1823
      48.44%     0.00%  random.h:1814
      46.74%     2.53%  random.h:185
      44.68%     0.10%  complex:589
      44.68%     0.00%  complex:597
      44.68%     0.00%  complex:654
      44.68%     0.00%  complex:664
      40.61%    13.80%  random.tcc:3330
      36.01%     0.00%  hypot+18446603487892193300
      26.81%     0.00%  random.h:151
      26.81%     0.00%  random.h:332
      25.75%    25.75%  random.h:143
       5.64%     0.00%  ??:0
       4.13%     4.13%  __hypot_finite+163
       4.13%     0.00%  __hypot_finite+18446603487892193443
...
~~~~~

Note that this change removes the symbol from the source:line hist
column. If this information is desired, users should explicitly query
for it if needed. I.e. run this command instead:

~~~~~
  perf report --inline -s sym,srcline -g none --stdio
  ...
  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 1K of event 'cycles:uppp'
  # Event count (approx.): 1381229476
  #
  # Children      Self  Symbol                                                                                                                               Source:Line
  # ........  ........  ...................................................................................................................................  ...........................................
  #
      94.30%     1.19%  [.] main                                                                                                                             main.cpp:39
      94.23%     0.00%  [.] __libc_start_main                                                                                                                __libc_start_main+18446603487898210537
      94.23%     0.00%  [.] _start                                                                                                                           _start+41
      48.44%     0.00%  [.] std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> > (inlined)  random.h:1814
      48.44%     0.00%  [.] std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> > (inlined)  random.h:1823
      46.74%     0.00%  [.] std::__detail::_Adaptor<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul>, double>::operator() (inlined)  random.h:185
      44.68%     0.00%  [.] std::_Norm_helper<true>::_S_do_it<double> (inlined)                                                                              complex:654
      44.68%     0.00%  [.] std::__complex_abs (inlined)                                                                                                     complex:589
      44.68%     0.00%  [.] std::abs<double> (inlined)                                                                                                       complex:597
      44.68%     0.00%  [.] std::norm<double> (inlined)                                                                                                      complex:664
      39.80%    13.59%  [.] std::generate_canonical<double, 53ul, std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> >               random.tcc:3330
      36.01%     0.00%  [.] hypot                                                                                                                            hypot+18446603487892193300
      26.81%     0.00%  [.] std::__detail::__mod<unsigned long, 2147483647ul, 16807ul, 0ul> (inlined)                                                        random.h:151
      26.81%     0.00%  [.] std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul>::operator() (inlined)                                 random.h:332
      25.75%     0.00%  [.] std::__detail::_Mod<unsigned long, 2147483647ul, 16807ul, 0ul, true, true>::__calc (inlined)                                     random.h:143
      25.19%    25.19%  [.] std::generate_canonical<double, 53ul, std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> >               random.h:143
       4.13%     4.13%  [.] __hypot_finite                                                                                                                   __hypot_finite+163
       4.13%     0.00%  [.] __hypot_finite                                                                                                                   __hypot_finite+18446603487892193443
...
~~~~~

Compared to the old behavior, this reduces duplication in the output.
Before we used to print the symbol name in the srcline column even
when the sym column was explicitly requested. I.e. the output was:

~~~~~
  perf report --inline -s sym,srcline -g none --stdio
  ...
  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 1K of event 'cycles:uppp'
  # Event count (approx.): 1381229476
  #
  # Children      Self  Symbol                                                                                                                               Source:Line
  # ........  ........  ...................................................................................................................................  ..................................................................................................................................
  #
      94.23%     0.00%  [.] __libc_start_main                                                                                                                __libc_start_main+18446603487898210537
      94.23%     0.00%  [.] _start                                                                                                                           _start+41
      44.58%     0.00%  [.] main                                                                                                                             main+100
      44.58%     0.00%  [.] std::_Norm_helper<true>::_S_do_it<double> (inlined)                                                                              std::_Norm_helper<true>::_S_do_it<double>+100
      44.58%     0.00%  [.] std::__complex_abs (inlined)                                                                                                     std::__complex_abs+100
      44.58%     0.00%  [.] std::abs<double> (inlined)                                                                                                       std::abs<double>+100
      44.58%     0.00%  [.] std::norm<double> (inlined)                                                                                                      std::norm<double>+100
      36.01%     0.00%  [.] hypot                                                                                                                            hypot+18446603487892193300
      25.81%     0.00%  [.] main                                                                                                                             main+41
      25.81%     0.00%  [.] std::__detail::_Adaptor<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul>, double>::operator() (inlined)  std::__detail::_Adaptor<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul>, double>::operator()+41
      25.81%     0.00%  [.] std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> > (inlined)  std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> >+41
      25.69%    25.69%  [.] std::generate_canonical<double, 53ul, std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> >               random.h:143
      18.39%     0.00%  [.] main                                                                                                                             main+57
      18.39%     0.00%  [.] std::__detail::_Adaptor<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul>, double>::operator() (inlined)  std::__detail::_Adaptor<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul>, double>::operator()+57
      18.39%     0.00%  [.] std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> > (inlined)  std::uniform_real_distribution<double>::operator()<std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> >+57
      13.80%    13.80%  [.] std::generate_canonical<double, 53ul, std::linear_congruential_engine<unsigned long, 16807ul, 0ul, 2147483647ul> >               random.tcc:3330
       4.13%     4.13%  [.] __hypot_finite                                                                                                                   __hypot_finite+163
       4.13%     0.00%  [.] __hypot_finite                                                                                                                   __hypot_finite+18446603487892193443
...
~~~~~
Signed-off-by: NMilian Wolff <milian.wolff@kdab.com>
Reviewed-by: NAndi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171019113836.5548-5-milian.wolff@kdab.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      1fb7d06a
  23. 03 10月, 2017 2 次提交
    • K
      perf top: Add option to set the number of thread for event synthesize · 0c6b4994
      由 Kan Liang 提交于 
      Using UINT_MAX to indicate the default thread#, which is the max number
of online CPU.

Committer testing:

  # perf trace --no-inherit -e clone -o /tmp/output perf top --num-thread-synthesize 9
  # cat /tmp/output
         ? (     ?   ):  ... [continued]: clone()) = 26651 (perf)
     0.059 ( 0.010 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7f5bfac44f30, parent_tidptr: 0x7f5bfac459d0, child_tidptr: 0x7f5bfac459d0, tls: 0x7f5bfac45700) = 26652 (perf)
     0.116 ( 0.014 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7f5bfa443f30, parent_tidptr: 0x7f5bfa4449d0, child_tidptr: 0x7f5bfa4449d0, tls: 0x7f5bfa444700) = 26653 (perf)
     0.141 ( 0.009 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7f5bf9c42f30, parent_tidptr: 0x7f5bf9c439d0, child_tidptr: 0x7f5bf9c439d0, tls: 0x7f5bf9c43700) = 26654 (perf)
     0.160 ( 0.012 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7f5bf9441f30, parent_tidptr: 0x7f5bf94429d0, child_tidptr: 0x7f5bf94429d0, tls: 0x7f5bf9442700) = 26655 (perf)
     0.232 ( 0.013 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7f5bf8c40f30, parent_tidptr: 0x7f5bf8c419d0, child_tidptr: 0x7f5bf8c419d0, tls: 0x7f5bf8c41700) = 26656 (perf)
     0.393 ( 0.011 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7f5be3ffef30, parent_tidptr: 0x7f5be3fff9d0, child_tidptr: 0x7f5be3fff9d0, tls: 0x7f5be3fff700) = 26657 (perf)
     0.802 ( 0.012 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7f5be37fdf30, parent_tidptr: 0x7f5be37fe9d0, child_tidptr: 0x7f5be37fe9d0, tls: 0x7f5be37fe700) = 26658 (perf)
     1.411 ( 0.022 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7f5be2ffcf30, parent_tidptr: 0x7f5be2ffd9d0, child_tidptr: 0x7f5be2ffd9d0, tls: 0x7f5be2ffd700) = 26659 (perf)
   246.422 ( 0.042 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7f5be2ffcf30, parent_tidptr: 0x7f5be2ffd9d0, child_tidptr: 0x7f5be2ffd9d0, tls: 0x7f5be2ffd700) = 26660 (perf)
  #
Signed-off-by: NKan Liang <kan.liang@intel.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Lukasz Odzioba <lukasz.odzioba@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1506696477-146932-5-git-send-email-kan.liang@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      0c6b4994
    • K
      perf top: Implement multithreading for perf_event__synthesize_threads · 340b47f5
      由 Kan Liang 提交于 
      The proc files which is sorted with alphabetical order are evenly
assigned to several synthesize threads to be processed in parallel.

For 'perf top', the threads number hard code to online CPU number. The
following patch will introduce an option to set it.

For other perf tools, the thread number is 1. Because the process
function is not ready for multithreading, e.g.
process_synthesized_event.

This patch series only support event synthesize multithreading for 'perf
top'. For other tools, it can be done separately later.

With multithread applied, the total processing time can get up to 1.56x
speedup on Knights Mill for 'perf top'.

For specific single event processing, the processing time could increase
because of the lock contention. So proc_map_timeout may need to be
increased. Otherwise some proc maps will be truncated.

Based on my test, increasing the proc_map_timeout has small impact
on the total processing time. The total processing time still get 1.49x
speedup on Knights Mill after increasing the proc_map_timeout.
The patch itself doesn't increase the proc_map_timeout.

Doesn't need to implement multithreading for per task monitoring,
perf_event__synthesize_thread_map. It doesn't have performance issue.

Committer testing:

  # getconf _NPROCESSORS_ONLN
  4
  # perf trace --no-inherit -e clone -o /tmp/output perf top
  # tail -4 /tmp/bla
     0.124 ( 0.041 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7fc3eb3a8f30, parent_tidptr: 0x7fc3eb3a99d0, child_tidptr: 0x7fc3eb3a99d0, tls: 0x7fc3eb3a9700) = 9548 (perf)
     0.246 ( 0.023 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7fc3eaba7f30, parent_tidptr: 0x7fc3eaba89d0, child_tidptr: 0x7fc3eaba89d0, tls: 0x7fc3eaba8700) = 9549 (perf)
     0.286 ( 0.019 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7fc3ea3a6f30, parent_tidptr: 0x7fc3ea3a79d0, child_tidptr: 0x7fc3ea3a79d0, tls: 0x7fc3ea3a7700) = 9550 (perf)
   246.540 ( 0.047 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7fc3ea3a6f30, parent_tidptr: 0x7fc3ea3a79d0, child_tidptr: 0x7fc3ea3a79d0, tls: 0x7fc3ea3a7700) = 9551 (perf)
  #
Signed-off-by: NKan Liang <kan.liang@intel.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Lukasz Odzioba <lukasz.odzioba@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1506696477-146932-4-git-send-email-kan.liang@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      340b47f5
  25. 13 9月, 2017 2 次提交
  27. 19 7月, 2017 1 次提交
    • D
      perf tools: Add feature header record to pipe-mode · e9def1b2
      由 David Carrillo-Cisneros 提交于 
      Add header record types to pipe-mode, reusing the functions
used in file-mode and leveraging the new struct feat_fd.

For alignment, check that synthesized events don't exceed
pagesize.

Add the perf_event__synthesize_feature event call back to
process the new header records.

Before this patch:

  $ perf record -o - -e cycles sleep 1 | perf report --stdio --header
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.000 MB - ]
  ...

After this patch:
  $ perf record -o - -e cycles sleep 1 | perf report --stdio --header
  # ========
  # captured on: Mon May 22 16:33:43 2017
  # ========
  #
  # hostname : my_hostname
  # os release : 4.11.0-dbx-up_perf
  # perf version : 4.11.rc6.g6277c80
  # arch : x86_64
  # nrcpus online : 72
  # nrcpus avail : 72
  # cpudesc : Intel(R) Xeon(R) CPU E5-2696 v3 @ 2.30GHz
  # cpuid : GenuineIntel,6,63,2
  # total memory : 263457192 kB
  # cmdline : /root/perf record -o - -e cycles -c 100000 sleep 1
  # HEADER_CPU_TOPOLOGY info available, use -I to display
  # HEADER_NUMA_TOPOLOGY info available, use -I to display
  # pmu mappings: intel_bts = 6, uncore_imc_4 = 22, uncore_sbox_1 = 47, uncore_cbox_5 = 33, uncore_ha_0 = 16, uncore_cbox
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.000 MB - ]
  ...

Support added for the subcommands: report, inject, annotate and script.
Signed-off-by: NDavid Carrillo-Cisneros <davidcc@google.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Que <sque@chromium.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20170718042549.145161-16-davidcc@google.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      e9def1b2
  29. 03 5月, 2017 1 次提交
    • A
      perf symbols: Accept symbols starting at address 0 · b843f62a
      由 Arnaldo Carvalho de Melo 提交于 
      That is the case of _text on s390, and we have some functions that return an
address, using address zero to report problems, oops.

This would lead the symbol loading routines to not use "_text" as the reference
relocation symbol, or the first symbol for the kernel, but use instead
"_stext", that is at the same address on x86_64 and others, but not on s390:

  [acme@localhost perf-4.11.0-rc6]$ head -15 /proc/kallsyms
  0000000000000000 T _text
  0000000000000418 t iplstart
  0000000000000800 T start
  000000000000080a t .base
  000000000000082e t .sk8x8
  0000000000000834 t .gotr
  0000000000000842 t .cmd
  0000000000000846 t .parm
  000000000000084a t .lowcase
  0000000000010000 T startup
  0000000000010010 T startup_kdump
  0000000000010214 t startup_kdump_relocated
  0000000000011000 T startup_continue
  00000000000112a0 T _ehead
  0000000000100000 T _stext
  [acme@localhost perf-4.11.0-rc6]$

Which in turn would make 'perf test vmlinux' to fail because it wouldn't find
the symbols before "_stext" in kallsyms.

Fix it by using the return value only for errors and storing the
address, when the symbol is successfully found, in a provided pointer
arg.

Before this patch:

After:

  [acme@localhost perf-4.11.0-rc6]$ tools/perf/perf test -v 1
   1: vmlinux symtab matches kallsyms            :
  --- start ---
  test child forked, pid 40693
  Looking at the vmlinux_path (8 entries long)
  Using /usr/lib/debug/lib/modules/3.10.0-654.el7.s390x/vmlinux for symbols
  ERR : 0: _text not on kallsyms
  ERR : 0x418: iplstart not on kallsyms
  ERR : 0x800: start not on kallsyms
  ERR : 0x80a: .base not on kallsyms
  ERR : 0x82e: .sk8x8 not on kallsyms
  ERR : 0x834: .gotr not on kallsyms
  ERR : 0x842: .cmd not on kallsyms
  ERR : 0x846: .parm not on kallsyms
  ERR : 0x84a: .lowcase not on kallsyms
  ERR : 0x10000: startup not on kallsyms
  ERR : 0x10010: startup_kdump not on kallsyms
  ERR : 0x10214: startup_kdump_relocated not on kallsyms
  ERR : 0x11000: startup_continue not on kallsyms
  ERR : 0x112a0: _ehead not on kallsyms
  <SNIP warnings>
  test child finished with -1
  ---- end ----
  vmlinux symtab matches kallsyms: FAILED!
  [acme@localhost perf-4.11.0-rc6]$

After:

  [acme@localhost perf-4.11.0-rc6]$ tools/perf/perf test -v 1
   1: vmlinux symtab matches kallsyms            :
  --- start ---
  test child forked, pid 47160
  <SNIP warnings>
  test child finished with 0
  ---- end ----
  vmlinux symtab matches kallsyms: Ok
  [acme@localhost perf-4.11.0-rc6]$
Reported-by: NMichael Petlan <mpetlan@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-9x9bwgd3btwdk1u51xie93fz@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      b843f62a
  31. 26 4月, 2017 1 次提交
  33. 25 4月, 2017 2 次提交
  35. 20 4月, 2017 6 次提交
  37. 13 4月, 2017 1 次提交
  39. 12 4月, 2017 1 次提交
  41. 17 3月, 2017 1 次提交
    • A
      perf tools: Handle partial AUX records and print a warning · 05a1f47e
      由 Alexander Shishkin 提交于 
      This patch decodes the 'partial' flag in AUX records and prints
a warning to the user, so that they don't have to guess why their
PT traces contain gaps (or missing altogether):

  Warning:
  AUX data had gaps in it 8 times out of 8!

  Are you running a KVM guest in the background?

Trying to be even more helpful, we will detect if the user's kvm driver sets up
exclusive VMX root mode for the entire lifespan of the kvm process:

  Reloading kvm_intel module with vmm_exclusive=0
  will reduce the gaps to only guest's timeslices.

Note however, that you'll still have gaps in cpu-wide traces even with
vmm_exclusive=0, but the number of gaps will be below 100% (as opposed to the
above example).

Currently this is the only reason for partial records.
Signed-off-by: NAlexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vince@deater.net>
Link: http://lkml.kernel.org/r/8760j941ig.fsf@ashishki-desk.ger.corp.intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      05a1f47e
  43. 16 3月, 2017 1 次提交
    • S
      perf tools: Make perf_event__synthesize_mmap_events() scale · 88b897a3
      由 Stephane Eranian 提交于 
      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 :
b18cb64e ("fs/proc: Stop trying to report thread stacks").
Signed-off-by: NStephane Eranian <eranian@google.com>
Acked-by: NJiri Olsa <jolsa@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170315135059.GC2177@redhat.com
Link: http://lkml.kernel.org/r/1489598233-25586-1-git-send-email-eranian@google.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      88b897a3