<feed xmlns='http://www.w3.org/2005/Atom'>
<title>BMC/Intel-BMC/linux.git/tools/perf/util/evlist.c, branch dev-5.2</title>
<subtitle>Intel OpenBMC Linux kernel source tree (mirror)</subtitle>
<id>https://git.radix-linux.su/BMC/Intel-BMC/linux.git/atom?h=dev-5.2</id>
<link rel='self' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/atom?h=dev-5.2'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/'/>
<updated>2019-06-05T15:30:26+00:00</updated>
<entry>
<title>treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 251</title>
<updated>2019-06-05T15:30:26+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2019-05-29T14:12:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=910070454e64d23396839f1f08ee84b7b9dc9bc5'/>
<id>urn:sha1:910070454e64d23396839f1f08ee84b7b9dc9bc5</id>
<content type='text'>
Based on 1 normalized pattern(s):

  released under the gpl v2 and only v2 not any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 12 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Steve Winslow &lt;swinslow@gmail.com&gt;
Reviewed-by: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Reviewed-by: Kate Stewart &lt;kstewart@linuxfoundation.org&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141332.526460839@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>perf mmap: Implement dedicated memory buffer for data compression</title>
<updated>2019-05-15T19:36:49+00:00</updated>
<author>
<name>Alexey Budankov</name>
<email>alexey.budankov@linux.intel.com</email>
</author>
<published>2019-03-18T17:42:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=51255a8af7c41c876c2d715a35ab03c13302a607'/>
<id>urn:sha1:51255a8af7c41c876c2d715a35ab03c13302a607</id>
<content type='text'>
Implemented mmap data buffer that is used as the memory to operate
on when compressing data in case of serial trace streaming.

Signed-off-by: Alexey Budankov &lt;alexey.budankov@linux.intel.com&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lkml.kernel.org/r/49b31321-0f70-392b-9a4f-649d3affe090@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2019-05-06T21:16:36+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-05-06T21:16:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=90489a72fba9529c85e051067ecb41183b8e982e'/>
<id>urn:sha1:90489a72fba9529c85e051067ecb41183b8e982e</id>
<content type='text'>
Pull perf updates from Ingo Molnar:
 "The main kernel changes were:

   - add support for Intel's "adaptive PEBS v4" - which embedds LBS data
     in PEBS records and can thus batch up and reduce the IRQ (NMI) rate
     significantly - reducing overhead and making call-graph profiling
     less intrusive.

   - add Intel CPU core and uncore support updates for Tremont, Icelake,

   - extend the x86 PMU constraints scheduler with 'constraint ranges'
     to better support Icelake hw constraints,

   - make x86 call-chain support work better with CONFIG_FRAME_POINTER=y

   - misc other changes

  Tooling changes:

   - updates to the main tools: 'perf record', 'perf trace', 'perf
     stat'

   - updated Intel and S/390 vendor events

   - libtraceevent updates

   - misc other updates and fixes"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (69 commits)
  perf/x86: Make perf callchains work without CONFIG_FRAME_POINTER
  watchdog: Fix typo in comment
  perf/x86/intel: Add Tremont core PMU support
  perf/x86/intel/uncore: Add Intel Icelake uncore support
  perf/x86/msr: Add Icelake support
  perf/x86/intel/rapl: Add Icelake support
  perf/x86/intel/cstate: Add Icelake support
  perf/x86/intel: Add Icelake support
  perf/x86: Support constraint ranges
  perf/x86/lbr: Avoid reading the LBRs when adaptive PEBS handles them
  perf/x86/intel: Support adaptive PEBS v4
  perf/x86/intel/ds: Extract code of event update in short period
  perf/x86/intel: Extract memory code PEBS parser for reuse
  perf/x86: Support outputting XMM registers
  perf/x86/intel: Force resched when TFA sysctl is modified
  perf/core: Add perf_pmu_resched() as global function
  perf/headers: Fix stale comment for struct perf_addr_filter
  perf/core: Make perf_swevent_init_cpu() static
  perf/x86: Add sanity checks to x86_schedule_events()
  perf/x86: Optimize x86_schedule_events()
  ...
</content>
</entry>
<entry>
<title>perf evlist: Fix side band thread draining</title>
<updated>2019-04-17T17:30:11+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2019-04-16T16:01:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=adc6257c4a6f23ff97dca8314fcd33828e2d8db5'/>
<id>urn:sha1:adc6257c4a6f23ff97dca8314fcd33828e2d8db5</id>
<content type='text'>
Current perf_evlist__poll_thread() code could finish without draining
the data. Adding the logic that makes sure we won't finish before the
drain.

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Fixes: 657ee5531903 ("perf evlist: Introduce side band thread")
Link: http://lkml.kernel.org/r/20190416160127.30203-9-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf record: Implement --mmap-flush=&lt;number&gt; option</title>
<updated>2019-04-01T18:18:10+00:00</updated>
<author>
<name>Alexey Budankov</name>
<email>alexey.budankov@linux.intel.com</email>
</author>
<published>2019-03-18T17:40:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=470530bbb8fbbf2a09bd1d7150bb92501c5c54e6'/>
<id>urn:sha1:470530bbb8fbbf2a09bd1d7150bb92501c5c54e6</id>
<content type='text'>
Implement a --mmap-flush option that specifies minimal number of bytes
that is extracted from mmaped kernel buffer to store into a trace. The
default option value is 1 byte what means every time trace writing
thread finds some new data in the mmaped buffer the data is extracted,
possibly compressed and written to a trace.

  $ tools/perf/perf record --mmap-flush 1024 -e cycles -- matrix.gcc
  $ tools/perf/perf record --aio --mmap-flush 1K -e cycles -- matrix.gcc

The option is independent from -z setting, doesn't vary with compression
level and can serve two purposes.

The first purpose is to increase the compression ratio of a trace data.
Larger data chunks are compressed more effectively so the implemented
option allows specifying data chunk size to compress. Also at some cases
executing more write syscalls with smaller data size can take longer
than executing less write syscalls with bigger data size due to syscall
overhead so extracting bigger data chunks specified by the option value
could additionally decrease runtime overhead.

The second purpose is to avoid self monitoring live-lock issue in system
wide (-a) profiling mode. Profiling in system wide mode with compression
(-a -z) can additionally induce data into the kernel buffers along with
the data from monitored processes. If performance data rate and volume
from the monitored processes is high then trace streaming and
compression activity in the tool is also high. High tool process
activity can lead to subtle live-lock effect when compression of single
new byte from some of mmaped kernel buffer leads to generation of the
next single byte at some mmaped buffer. So perf tool process ends up in
endless self monitoring.

Implemented synch parameter is the mean to force data move independently
from the specified flush threshold value. Despite the provided flush
value the tool needs capability to unconditionally drain memory buffers,
at least in the end of the collection.

Committer testing:

Running with the default value, i.e. as soon as there is something to
read go on consuming, we first write the synthesized events, small
chunks of about 128 bytes:

  # perf trace -m 2048 --call-graph dwarf -e write -- perf record
  &lt;SNIP&gt;
     101.142 ( 0.004 ms): perf/25821 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x210db60, count: 120) = 120
                                         __libc_write (/usr/lib64/libpthread-2.28.so)
                                         ion (/home/acme/bin/perf)
                                         record__write (inlined)
                                         process_synthesized_event (/home/acme/bin/perf)
                                         perf_tool__process_synth_event (inlined)
                                         perf_event__synthesize_mmap_events (/home/acme/bin/perf)

Then we move to reading the mmap buffers consuming the events put there
by the kernel perf infrastructure:

     107.561 ( 0.005 ms): perf/25821 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x7f1befc02000, count: 336) = 336
                                         __libc_write (/usr/lib64/libpthread-2.28.so)
                                         ion (/home/acme/bin/perf)
                                         record__write (inlined)
                                         record__pushfn (/home/acme/bin/perf)
                                         perf_mmap__push (/home/acme/bin/perf)
                                         record__mmap_read_evlist (inlined)
                                         record__mmap_read_all (inlined)
                                         __cmd_record (inlined)
                                         cmd_record (/home/acme/bin/perf)
     12919.953 ( 0.136 ms): perf/25821 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x7f1befc83150, count: 184984) = 184984
  &lt;SNIP same backtrace as in the 107.561 timestamp&gt;
     12920.094 ( 0.155 ms): perf/25821 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x7f1befc02150, count: 261816) = 261816
  &lt;SNIP same backtrace as in the 107.561 timestamp&gt;
     12920.253 ( 0.093 ms): perf/25821 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x7f1befb81120, count: 170832) = 170832
  &lt;SNIP same backtrace as in the 107.561 timestamp&gt;

If we limit it to write only when more than 16MB are available for
reading, it throttles that to a quarter of the --mmap-pages set for
'perf record', which by default get to 528384 bytes, found out using
'record -v':

  mmap flush: 132096
  mmap size 528384B

With that in place all the writes coming from
record__mmap_read_evlist(), i.e. from the mmap buffers setup by the
kernel perf infrastructure were at least 132096 bytes long.

Trying with a bigger mmap size:

   perf trace -e write perf record -v -m 2048 --mmap-flush 16M
   74982.928 ( 2.471 ms): perf/26500 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x7ff94a6cc000, count: 3580888) = 3580888
   74985.406 ( 2.353 ms): perf/26500 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x7ff949ecb000, count: 3453256) = 3453256
   74987.764 ( 2.629 ms): perf/26500 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x7ff9496ca000, count: 3859232) = 3859232
   74990.399 ( 2.341 ms): perf/26500 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x7ff948ec9000, count: 3769032) = 3769032
   74992.744 ( 2.064 ms): perf/26500 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x7ff9486c8000, count: 3310520) = 3310520
   74994.814 ( 2.619 ms): perf/26500 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x7ff947ec7000, count: 4194688) = 4194688
   74997.439 ( 2.787 ms): perf/26500 write(fd: 3&lt;/root/perf.data&gt;, buf: 0x7ff9476c6000, count: 4029760) = 4029760

Was again limited to a quarter of the mmap size:

  mmap flush: 2098176
  mmap size 8392704B

A warning about that would be good to have but can be added later,
something like:

  "max flush is a quarter of the mmap size, if wanting to bump the mmap
   flush further, bump the mmap size as well using -m/--mmap-pages"

Also rename the 'sync' parameters to 'synch' to keep tools/perf building
with older glibcs:

  cc1: warnings being treated as errors
  builtin-record.c: In function 'record__mmap_read_evlist':
  builtin-record.c:775: warning: declaration of 'sync' shadows a global declaration
  /usr/include/unistd.h:933: warning: shadowed declaration is here
  builtin-record.c: In function 'record__mmap_read_all':
  builtin-record.c:856: warning: declaration of 'sync' shadows a global declaration
  /usr/include/unistd.h:933: warning: shadowed declaration is here

Signed-off-by: Alexey Budankov &lt;alexey.budankov@linux.intel.com&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@kernel.org&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: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lkml.kernel.org/r/f6600d72-ecfa-2eb7-7e51-f6954547d500@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf evsel: Fix max perf_event_attr.precise_ip detection</title>
<updated>2019-03-28T17:31:56+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2019-03-14T14:00:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=4e8a5c1551370ebc0fbdb8f5c33dad13e45bdc99'/>
<id>urn:sha1:4e8a5c1551370ebc0fbdb8f5c33dad13e45bdc99</id>
<content type='text'>
After a discussion with Andi, move the perf_event_attr.precise_ip
detection for maximum precise config (via :P modifier or for default
cycles event) to perf_evsel__open().

The current detection in perf_event_attr__set_max_precise_ip() is
tricky, because precise_ip config is specific for given event and it
currently checks only hw cycles.

We now check for valid precise_ip value right after failing
sys_perf_event_open() for specific event, before any of the
perf_event_attr fallback code gets executed.

This way we get the proper config in perf_event_attr together with
allowed precise_ip settings.

We can see that code activity with -vv, like:

  $ perf record -vv ls
  ...
  ------------------------------------------------------------
  perf_event_attr:
    size                             112
    { sample_period, sample_freq }   4000
    ...
    precise_ip                       3
    sample_id_all                    1
    exclude_guest                    1
    mmap2                            1
    comm_exec                        1
    ksymbol                          1
  ------------------------------------------------------------
  sys_perf_event_open: pid 9926  cpu 0  group_fd -1  flags 0x8
  sys_perf_event_open failed, error -95
  decreasing precise_ip by one (2)
  ------------------------------------------------------------
  perf_event_attr:
    size                             112
    { sample_period, sample_freq }   4000
    ...
    precise_ip                       2
    sample_id_all                    1
    exclude_guest                    1
    mmap2                            1
    comm_exec                        1
    ksymbol                          1
  ------------------------------------------------------------
  sys_perf_event_open: pid 9926  cpu 0  group_fd -1  flags 0x8 = 4
  ...

Suggested-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: http://lkml.kernel.org/n/tip-dkvxxbeg7lu74155d4jhlmc9@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf evlist: Introduce side band thread</title>
<updated>2019-03-21T14:27:03+00:00</updated>
<author>
<name>Song Liu</name>
<email>songliubraving@fb.com</email>
</author>
<published>2019-03-12T05:30:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=657ee5531903339b06697581532ed32d4762526e'/>
<id>urn:sha1:657ee5531903339b06697581532ed32d4762526e</id>
<content type='text'>
This patch introduces side band thread that captures extended
information for events like PERF_RECORD_BPF_EVENT.

This new thread uses its own evlist that uses ring buffer with very low
watermark for lower latency.

To use side band thread, we need to:

1. add side band event(s) by calling perf_evlist__add_sb_event();
2. calls perf_evlist__start_sb_thread();
3. at the end of perf run, perf_evlist__stop_sb_thread().

In the next patch, we use this thread to handle PERF_RECORD_BPF_EVENT.

Committer notes:

Add fix by Jiri Olsa for when te sb_tread can't get started and then at
the end the stop_sb_thread() segfaults when joining the (non-existing)
thread.

That can happen when running 'perf top' or 'perf record' as a normal
user, for instance.

Further checks need to be done on top of this to more graciously handle
these possible failure scenarios.

Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Stanislav Fomichev &lt;sdf@google.com&gt;
Link: http://lkml.kernel.org/r/20190312053051.2690567-15-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf evsel: Probe for precise_ip with simple attr</title>
<updated>2019-03-06T21:19:45+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2019-03-05T15:25:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=5b61adb16599be04346e7e943c1b5113b57485ad'/>
<id>urn:sha1:5b61adb16599be04346e7e943c1b5113b57485ad</id>
<content type='text'>
Currently we probe for precise_ip with user specified perf_event_attr,
which might fail because of unsupported kernel features, which would get
disabled during the open time anyway.

Switching the probe to take place on simple hw cycles, so the following
record sets proper precise_ip:

  # perf record -e cycles:P ls
  # perf evlist -v
  cycles:P: size: 112, ... precise_ip: 3, ...

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jonas Rabenstein &lt;jonas.rabenstein@studium.uni-erlangen.de&gt;
Cc: Nageswara R Sastry &lt;nasastry@in.ibm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@linux.ibm.com&gt;
Link: http://lkml.kernel.org/r/20190305152536.21035-7-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf record: Allocate affinity masks</title>
<updated>2019-02-06T13:00:39+00:00</updated>
<author>
<name>Alexey Budankov</name>
<email>alexey.budankov@linux.intel.com</email>
</author>
<published>2019-01-22T17:47:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=9d2ed64587c045304efe8872b0258c30803d370c'/>
<id>urn:sha1:9d2ed64587c045304efe8872b0258c30803d370c</id>
<content type='text'>
Allocate affinity option and masks for mmap data buffers and record
thread as well as initialize allocated objects.

Signed-off-by: Alexey Budankov &lt;alexey.budankov@linux.intel.com&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lkml.kernel.org/r/526fa2b0-07de-6dbd-a7e9-26ba875593c9@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf tools: Add missing sigqueue() prototype for systems lacking it</title>
<updated>2018-12-18T15:23:56+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2018-12-11T18:48:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/BMC/Intel-BMC/linux.git/commit/?id=748fe0889c1ff12d378946bd5326e8ee8eacf5cf'/>
<id>urn:sha1:748fe0889c1ff12d378946bd5326e8ee8eacf5cf</id>
<content type='text'>
There are systems such as the Android NDK API level 24 has the
sigqueue() function but doesn't provide a prototype, adding noise to the
build:

  util/evlist.c: In function 'perf_evlist__prepare_workload':
  util/evlist.c:1494:4: warning: implicit declaration of function 'sigqueue' [-Wimplicit-function-declaration]
      if (sigqueue(getppid(), SIGUSR1, val))
      ^
  util/evlist.c:1494:4: warning: nested extern declaration of 'sigqueue' [-Wnested-externs]

Define a LACKS_SIGQUEUE_PROTOTYPE define so that code needing that can
get a prototype.

Checked in the bionic git repo to be available since level 23:

https://android.googlesource.com/platform/bionic/+/master/libc/include/signal.h#123

  int sigqueue(pid_t __pid, int __signal, const union sigval __value) __INTRODUCED_IN(23);

Cc: Adrian Hunter &lt;adrian.hunter@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-lmhpev1uni9kdrv7j29glyov@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
</feed>
