<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel.git/tools/perf/util/symbol.c, branch linux-5.7.y</title>
<subtitle>Hosts the 0x221E linux distro kernel.
</subtitle>
<id>https://git.0xinfinity.dev/distro/kernel.git/atom?h=linux-5.7.y</id>
<link rel='self' href='https://git.0xinfinity.dev/distro/kernel.git/atom?h=linux-5.7.y'/>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/'/>
<updated>2020-06-22T07:33:12Z</updated>
<entry>
<title>perf symbols: Fix kernel maps for kcore and eBPF</title>
<updated>2020-06-22T07:33:12Z</updated>
<author>
<name>Adrian Hunter</name>
</author>
<published>2020-06-02T11:25:05Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=29e428a8372e99979f1af474fb6502fe62d38ed9'/>
<id>urn:sha1:29e428a8372e99979f1af474fb6502fe62d38ed9</id>
<content type='text'>
commit 0affd0e5262b6d40f5f63466d88933e99698e240 upstream.

Adjust 'map-&gt;pgoff' also when moving a map's start address.

Example with v5.4.34 based kernel:

  Before:

    $ sudo tools/perf/perf record -a --kcore -e intel_pt//k sleep 1
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 1.958 MB perf.data ]
    $ sudo tools/perf/perf script --itrace=e &gt;/dev/null
    Warning:
    961 instruction trace errors

  After:

    $ sudo tools/perf/perf script --itrace=e &gt;/dev/null
    $

Committer testing:

  # uname -a
  Linux seventh 5.6.10-100.fc30.x86_64 #1 SMP Mon May 4 15:36:44 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
  #

Before:

  # perf record -a --kcore -e intel_pt//k sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.923 MB perf.data ]
  # perf script --itrace=e &gt;/dev/null
  Warning:
  295 instruction trace errors
  #

After:

  # perf record -a --kcore -e intel_pt//k sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.919 MB perf.data ]
  # perf script --itrace=e &gt;/dev/null
  #

Fixes: fb5a88d4131a ("perf tools: Preserve eBPF maps when loading kcore")
Signed-off-by: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200602112505.1406-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>perf symbols: Fix debuginfo search for Ubuntu</title>
<updated>2020-06-22T07:33:12Z</updated>
<author>
<name>Adrian Hunter</name>
</author>
<published>2020-05-26T15:52:07Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=6fb0a018f15d90180bb92d31885aa70625af2bcc'/>
<id>urn:sha1:6fb0a018f15d90180bb92d31885aa70625af2bcc</id>
<content type='text'>
commit 85afd35575a3c1a3a905722dde5ee70b49282e70 upstream.

Reportedly, from 19.10 Ubuntu has begun mixing up the location of some
debug symbol files, putting files expected to be in
/usr/lib/debug/usr/lib into /usr/lib/debug/lib instead. Fix by adding
another dso_binary_type.

Example on Ubuntu 20.04

  Before:

    $ perf record -e intel_pt//u uname
    Linux
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.030 MB perf.data ]
    $ perf script --call-trace | head -5
           uname 14003 [005] 15321.764958566:  cbr: 42 freq: 4219 MHz (156%)
           uname 14003 [005] 15321.764958566: (/usr/lib/x86_64-linux-gnu/ld-2.31.so              )          7f1e71cc4100
           uname 14003 [005] 15321.764961566: (/usr/lib/x86_64-linux-gnu/ld-2.31.so              )              7f1e71cc4df0
           uname 14003 [005] 15321.764961900: (/usr/lib/x86_64-linux-gnu/ld-2.31.so              )              7f1e71cc4e18
           uname 14003 [005] 15321.764963233: (/usr/lib/x86_64-linux-gnu/ld-2.31.so              )              7f1e71cc5128

  After:

    $ perf script --call-trace | head -5
           uname 14003 [005] 15321.764958566:  cbr: 42 freq: 4219 MHz (156%)
           uname 14003 [005] 15321.764958566: (/usr/lib/x86_64-linux-gnu/ld-2.31.so              )      _start
           uname 14003 [005] 15321.764961566: (/usr/lib/x86_64-linux-gnu/ld-2.31.so              )          _dl_start
           uname 14003 [005] 15321.764961900: (/usr/lib/x86_64-linux-gnu/ld-2.31.so              )          _dl_start
           uname 14003 [005] 15321.764963233: (/usr/lib/x86_64-linux-gnu/ld-2.31.so              )          _dl_start

Reported-by: Travis Downs &lt;travis.downs@gmail.com&gt;
Signed-off-by: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200526155207.9172-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>perf symbols: Don't try to find a vmlinux file when looking for kernel modules</title>
<updated>2020-03-03T19:20:01Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
</author>
<published>2020-03-02T19:03:34Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=b5c0951860ba98cfe1936b5c0739450875d51451'/>
<id>urn:sha1:b5c0951860ba98cfe1936b5c0739450875d51451</id>
<content type='text'>
The dso-&gt;kernel value is now set to everything that is in
machine-&gt;kmaps, but that was being used to decide if vmlinux lookup is
needed, which ended up making that lookup be made for kernel modules,
that now have dso-&gt;kernel set, leading to these kinds of warnings when
running on a machine with compressed kernel modules, like fedora:31:

  [root@five ~]# perf record -F 10000 -a sleep 2
  [ perf record: Woken up 1 times to write data ]
  lzma: fopen failed on vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
  lzma: fopen failed on vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
  lzma: fopen failed on vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
  lzma: fopen failed on vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
  lzma: fopen failed on vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
  [ perf record: Captured and wrote 1.024 MB perf.data (1366 samples) ]
  [root@five ~]#

This happens when collecting the buildid, when we find samples for
kernel modules, fix it by checking if the looked up DSO is a kernel
module by other means.

Fixes: 02213cec64bb ("perf maps: Mark module DSOs with kernel type")
Tested-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Kim Phillips &lt;kim.phillips@amd.com&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@linux.ibm.com&gt;
Link: http://lore.kernel.org/lkml/20200302191007.GD10335@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf symbols: Convert symbol__is_idle() to use strlist</title>
<updated>2020-02-10T19:30:51Z</updated>
<author>
<name>Kim Phillips</name>
</author>
<published>2020-02-10T16:31:47Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=bc5f15be2c814ca1ff6bb4e62d5b275a8c88cbb1'/>
<id>urn:sha1:bc5f15be2c814ca1ff6bb4e62d5b275a8c88cbb1</id>
<content type='text'>
Use the more optimized strlist implementation to do the idle function
lookup.

Signed-off-by: Kim Phillips &lt;kim.phillips@amd.com&gt;
Acked-by: Song Liu &lt;songliubraving@fb.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Cc: Davidlohr Bueso &lt;dave@stgolabs.net&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20200210163147.25358-1-kim.phillips@amd.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf symbols: Update the list of kernel idle symbols</title>
<updated>2020-02-10T19:30:13Z</updated>
<author>
<name>Kim Phillips</name>
</author>
<published>2020-02-07T23:06:12Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=0e71459afcbbf69e92a65085c45515d3f3f02c31'/>
<id>urn:sha1:0e71459afcbbf69e92a65085c45515d3f3f02c31</id>
<content type='text'>
The "acpi_idle_do_entry", "acpi_processor_ffh_cstate_enter", and
"idle_cpu" symbols appear in 'perf top' output, at least on AMD systems.

Add them to perf's idle_symbols list, so they don't dominate 'perf top'
output.

Signed-off-by: Kim Phillips &lt;kim.phillips@amd.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Acked-by: Song Liu &lt;songliubraving@fb.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Cc: Davidlohr Bueso &lt;dave@stgolabs.net&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20200207230613.26709-2-kim.phillips@amd.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf maps: Rename 'mg' variables to 'maps'</title>
<updated>2019-11-26T14:07:46Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
</author>
<published>2019-11-26T01:21:28Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=9a29ceee6bb14aeb58ab2222c8e792576fe90fb8'/>
<id>urn:sha1:9a29ceee6bb14aeb58ab2222c8e792576fe90fb8</id>
<content type='text'>
Continuing the merge of 'struct maps' with 'struct map_groups'.

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lkml.kernel.org/n/tip-z8d14wrw393a0fbvmnk1bqd9@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf maps: Merge 'struct maps' with 'struct map_groups'</title>
<updated>2019-11-26T14:07:46Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
</author>
<published>2019-11-26T00:58:33Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=79b6bb73f888933cbcd20b0ef3976cde67951b72'/>
<id>urn:sha1:79b6bb73f888933cbcd20b0ef3976cde67951b72</id>
<content type='text'>
And pick the shortest name: 'struct maps'.

The split existed because we used to have two groups of maps, one for
functions and one for variables, but that only complicated things,
sometimes we needed to figure out what was at some address and then had
to first try it on the functions group and if that failed, fall back to
the variables one.

That split is long gone, so for quite a while we had only one struct
maps per struct map_groups, simplify things by combining those structs.

First patch is the minimum needed to merge both, follow up patches will
rename 'thread-&gt;mg' to 'thread-&gt;maps', etc.

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lkml.kernel.org/n/tip-hom6639ro7020o708trhxh59@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf map_groups: Auto sort maps by name, if needed</title>
<updated>2019-11-18T16:01:58Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
</author>
<published>2019-11-17T14:38:13Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=a7c2b572e217418ad34441202ad3addd8f94d2ea'/>
<id>urn:sha1:a7c2b572e217418ad34441202ad3addd8f94d2ea</id>
<content type='text'>
There are still lots of lookups by name, even if just when loading
vmlinux, till that code is studied to figure out if its possible to do
away with those map lookup by names, provide a way to sort it using
libc's qsort/bsearch.

Doing it at the first lookup defers the sorting a bit, and as the code
stands now, is never done for user maps, just for the kernel ones.

  # perf probe -l
  # perf probe -x ~/bin/perf -L __map_groups__find_by_name
  &lt;__map_groups__find_by_name@/home/acme/git/perf/tools/perf/util/symbol.c:0&gt;
        0  static struct map *__map_groups__find_by_name(struct map_groups *mg, const char *name)
        1  {
                  struct map **mapp;

        4         if (mg-&gt;maps_by_name == NULL &amp;&amp;
        5             map__groups__sort_by_name_from_rbtree(mg))
        6                 return NULL;

        8         mapp = bsearch(name, mg-&gt;maps_by_name, mg-&gt;nr_maps, sizeof(*mapp), map__strcmp_name);
        9         if (mapp)
       10                 return *mapp;
       11         return NULL;
       12  }

           struct map *map_groups__find_by_name(struct map_groups *mg, const char *name)
           {

  # perf probe -x ~/bin/perf 'found=__map_groups__find_by_name:10 name:string'
  Added new event:
    probe_perf:found     (on __map_groups__find_by_name:10 in /home/acme/bin/perf with name:string)

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

  	perf record -e probe_perf:found -aR sleep 1

  #
  # perf probe -x ~/bin/perf -L map_groups__find_by_name
  &lt;map_groups__find_by_name@/home/acme/git/perf/tools/perf/util/symbol.c:0&gt;
        0  struct map *map_groups__find_by_name(struct map_groups *mg, const char *name)
        1  {
        2         struct maps *maps = &amp;mg-&gt;maps;
                  struct map *map;

        5         down_read(&amp;maps-&gt;lock);

        7         if (mg-&gt;last_search_by_name &amp;&amp; strcmp(mg-&gt;last_search_by_name-&gt;dso-&gt;short_name, name) == 0) {
        8                 map = mg-&gt;last_search_by_name;
        9                 goto out_unlock;
                  }
                  /*
                   * If we have mg-&gt;maps_by_name, then the name isn't in the rbtree,
                   * as mg-&gt;maps_by_name mirrors the rbtree when lookups by name are
                   * made.
                   */
       16         map = __map_groups__find_by_name(mg, name);
       17         if (map || mg-&gt;maps_by_name != NULL)
       18                 goto out_unlock;

                  /* Fallback to traversing the rbtree... */
       21         maps__for_each_entry(maps, map)
       22                 if (strcmp(map-&gt;dso-&gt;short_name, name) == 0) {
       23                         mg-&gt;last_search_by_name = map;
       24                         goto out_unlock;
                          }

       27         map = NULL;

           out_unlock:
       30         up_read(&amp;maps-&gt;lock);
       31         return map;
       32  }

           int dso__load_vmlinux(struct dso *dso, struct map *map,
                                const char *vmlinux, bool vmlinux_allocated)

  # perf probe -x ~/bin/perf 'fallback=map_groups__find_by_name:21 name:string'
  Added new events:
    probe_perf:fallback  (on map_groups__find_by_name:21 in /home/acme/bin/perf with name:string)
    probe_perf:fallback_1 (on map_groups__find_by_name:21 in /home/acme/bin/perf with name:string)

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

  	perf record -e probe_perf:fallback_1 -aR sleep 1

  #
  # perf probe -l
    probe_perf:fallback  (on map_groups__find_by_name:21@util/symbol.c in /home/acme/bin/perf with name_string)
    probe_perf:fallback_1 (on map_groups__find_by_name:21@util/symbol.c in /home/acme/bin/perf with name_string)
    probe_perf:found     (on __map_groups__find_by_name:10@util/symbol.c in /home/acme/bin/perf with name_string)
  #
  # perf stat -e probe_perf:*

Now run 'perf top' in another term and then, after a while, stop 'perf stat':

Furthermore, if we ask for interval printing, we can see that that is done just
at the start of the workload:

  # perf stat -I1000 -e probe_perf:*
  #           time             counts unit events
       1.000319513                  0      probe_perf:found
       1.000319513                  0      probe_perf:fallback_1
       1.000319513                  0      probe_perf:fallback
       2.001868092             23,251      probe_perf:found
       2.001868092                  0      probe_perf:fallback_1
       2.001868092                  0      probe_perf:fallback
       3.002901597                  0      probe_perf:found
       3.002901597                  0      probe_perf:fallback_1
       3.002901597                  0      probe_perf:fallback
       4.003358591                  0      probe_perf:found
       4.003358591                  0      probe_perf:fallback_1
       4.003358591                  0      probe_perf:fallback
  ^C
  #

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lkml.kernel.org/n/tip-c5lmbyr14x448rcfii7y6t3k@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf machine: No need to check if kernel module maps pre-exist</title>
<updated>2019-11-18T16:01:50Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
</author>
<published>2019-11-14T15:28:41Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=a94ab91a54c63b9101715b03171219279cc0ee26'/>
<id>urn:sha1:a94ab91a54c63b9101715b03171219279cc0ee26</id>
<content type='text'>
We'only populating maps for kernel modules either from perf.data file
PERF_RECORD_MMAP records or when parsing /proc/modules, so there is no
need to first look if we already have those module maps in the list,
that would mean the kernel has duplicate entries.

So ditch one use of looking up maps by name.

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lkml.kernel.org/n/tip-gnzjg2hhuz6jnrw91m35059y@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf map_groups: Add a front end cache for map lookups by name</title>
<updated>2019-11-18T14:21:32Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
</author>
<published>2019-11-13T19:33:33Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=1ae14516cba032a83b561144d3d48fd381584c0c'/>
<id>urn:sha1:1ae14516cba032a83b561144d3d48fd381584c0c</id>
<content type='text'>
Lets see if it helps:

First look at the probeable lines for the function that does lookups by
name in a map_groups struct:

  # perf probe -x ~/bin/perf -L map_groups__find_by_name
  &lt;map_groups__find_by_name@/home/acme/git/perf/tools/perf/util/symbol.c:0&gt;
        0  struct map *map_groups__find_by_name(struct map_groups *mg, const char *name)
        1  {
        2         struct maps *maps = &amp;mg-&gt;maps;
                  struct map *map;

        5         down_read(&amp;maps-&gt;lock);

        7         if (mg-&gt;last_search_by_name &amp;&amp; strcmp(mg-&gt;last_search_by_name-&gt;dso-&gt;short_name, name) == 0) {
        8                 map = mg-&gt;last_search_by_name;
        9                 goto out_unlock;
                  }

       12         maps__for_each_entry(maps, map)
       13                 if (strcmp(map-&gt;dso-&gt;short_name, name) == 0) {
       14                         mg-&gt;last_search_by_name = map;
       15                         goto out_unlock;
                          }

       18         map = NULL;

           out_unlock:
       21         up_read(&amp;maps-&gt;lock);
       22         return map;
       23  }

           int dso__load_vmlinux(struct dso *dso, struct map *map,
                                const char *vmlinux, bool vmlinux_allocated)

  #

Now add a probe to the place where we reuse the last search:

  # perf probe -x ~/bin/perf map_groups__find_by_name:8
  Added new event:
    probe_perf:map_groups__find_by_name (on map_groups__find_by_name:8 in /home/acme/bin/perf)

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

  	perf record -e probe_perf:map_groups__find_by_name -aR sleep 1

  #

Now lets do a system wide 'perf stat' counting those events:

  # perf stat -e probe_perf:*

Leave it running and lets do a 'perf top', then, after a while, stop the
'perf stat':

  # perf stat -e probe_perf:*
  ^C
   Performance counter stats for 'system wide':

               3,603      probe_perf:map_groups__find_by_name

        44.565253139 seconds time elapsed
  #

yeah, good to have.

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lkml.kernel.org/n/tip-tcz37g3nxv3tvxw3q90vga3p@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
</feed>
