<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/tools, branch v4.16-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'perf-core-for-mingo-4.17-20180215' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent</title>
<updated>2018-02-16T08:10:09+00:00</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@kernel.org</email>
</author>
<published>2018-02-16T08:10:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3f9e6463132ac2447351805875d4e06b4fd51683'/>
<id>3f9e6463132ac2447351805875d4e06b4fd51683</id>
<content type='text'>
Pull perf/core fixes from Arnaldo Carvalho de Melo:

- perf_mmap overwrite mode fixes/overhaul, prep work to get 'perf top'
  using it, making it bearable to use it in large core count systems
  such as Knights Landing/Mill Intel systems (Kan Liang)

- s/390 now uses syscall.tbl, just like x86-64 to generate the syscall
  table id -&gt; string tables used by 'perf trace' (Hendrik Brueckner)

- Use strtoull() instead of home grown function (Andy Shevchenko)

- Synchronize kernel ABI headers, v4.16-rc1 (Ingo Molnar)

- Document missing 'perf data --force' option (Sangwon Hong)

- Add perf vendor JSON metrics for ARM Cortex-A53 Processor (William Cohen)

Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull perf/core fixes from Arnaldo Carvalho de Melo:

- perf_mmap overwrite mode fixes/overhaul, prep work to get 'perf top'
  using it, making it bearable to use it in large core count systems
  such as Knights Landing/Mill Intel systems (Kan Liang)

- s/390 now uses syscall.tbl, just like x86-64 to generate the syscall
  table id -&gt; string tables used by 'perf trace' (Hendrik Brueckner)

- Use strtoull() instead of home grown function (Andy Shevchenko)

- Synchronize kernel ABI headers, v4.16-rc1 (Ingo Molnar)

- Document missing 'perf data --force' option (Sangwon Hong)

- Add perf vendor JSON metrics for ARM Cortex-A53 Processor (William Cohen)

Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "tools include s390: Grab a copy of arch/s390/include/uapi/asm/unistd.h"</title>
<updated>2018-02-15T13:06:15+00:00</updated>
<author>
<name>Hendrik Brueckner</name>
<email>brueckner@linux.vnet.ibm.com</email>
</author>
<published>2018-02-08T11:47:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f1d0b4cde922863004ce3f5f39e8662cc0686c96'/>
<id>f1d0b4cde922863004ce3f5f39e8662cc0686c96</id>
<content type='text'>
This reverts commit f120c7b187e6c418238710b48723ce141f467543 which is no
longer required with the introduction of a syscall.tbl on s390.

Signed-off-by: Hendrik Brueckner &lt;brueckner@linux.vnet.ibm.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Thomas Richter &lt;tmricht@linux.vnet.ibm.com&gt;
Cc: linux-s390@vger.kernel.org
LPU-Reference: 1518090470-2899-2-git-send-email-brueckner@linux.vnet.ibm.com
Link: https://lkml.kernel.org/n/tip-q1lg0nvhha1tk39ri9aqalcb@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit f120c7b187e6c418238710b48723ce141f467543 which is no
longer required with the introduction of a syscall.tbl on s390.

Signed-off-by: Hendrik Brueckner &lt;brueckner@linux.vnet.ibm.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Thomas Richter &lt;tmricht@linux.vnet.ibm.com&gt;
Cc: linux-s390@vger.kernel.org
LPU-Reference: 1518090470-2899-2-git-send-email-brueckner@linux.vnet.ibm.com
Link: https://lkml.kernel.org/n/tip-q1lg0nvhha1tk39ri9aqalcb@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf s390: Rework system call table creation by using syscall.tbl</title>
<updated>2018-02-15T13:06:08+00:00</updated>
<author>
<name>Hendrik Brueckner</name>
<email>brueckner@linux.vnet.ibm.com</email>
</author>
<published>2018-02-08T11:47:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=690d22d9d4423b4522fb44a71145403eef2df834'/>
<id>690d22d9d4423b4522fb44a71145403eef2df834</id>
<content type='text'>
Recently, s390 uses a syscall.tbl input file to generate its system call
table and unistd uapi header files.  Hence, update mksyscalltbl to use
it as input to create the system table for perf.

Signed-off-by: Hendrik Brueckner &lt;brueckner@linux.vnet.ibm.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Thomas Richter &lt;tmricht@linux.vnet.ibm.com&gt;
Cc: linux-s390@vger.kernel.org
LPU-Reference: 1518090470-2899-4-git-send-email-brueckner@linux.vnet.ibm.com
Link: https://lkml.kernel.org/n/tip-bdyhllhsq1zgxv2qx4m377y6@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Recently, s390 uses a syscall.tbl input file to generate its system call
table and unistd uapi header files.  Hence, update mksyscalltbl to use
it as input to create the system table for perf.

Signed-off-by: Hendrik Brueckner &lt;brueckner@linux.vnet.ibm.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Thomas Richter &lt;tmricht@linux.vnet.ibm.com&gt;
Cc: linux-s390@vger.kernel.org
LPU-Reference: 1518090470-2899-4-git-send-email-brueckner@linux.vnet.ibm.com
Link: https://lkml.kernel.org/n/tip-bdyhllhsq1zgxv2qx4m377y6@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf s390: Grab a copy of arch/s390/kernel/syscall/syscall.tbl</title>
<updated>2018-02-15T13:06:00+00:00</updated>
<author>
<name>Hendrik Brueckner</name>
<email>brueckner@linux.vnet.ibm.com</email>
</author>
<published>2018-02-08T11:47:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=baa676103037e0dd145bb905eb51bc0b2f48fd49'/>
<id>baa676103037e0dd145bb905eb51bc0b2f48fd49</id>
<content type='text'>
Grab a copy of the s390 system call table file introduced with commit
857f46bfb07f53dc112d69bdfb137cc5ec3da7c5 "s390/syscalls: add system call
table".

Signed-off-by: Hendrik Brueckner &lt;brueckner@linux.vnet.ibm.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Thomas Richter &lt;tmricht@linux.vnet.ibm.com&gt;
Cc: linux-s390@vger.kernel.org
LPU-Reference: 1518090470-2899-3-git-send-email-brueckner@linux.vnet.ibm.com
Link: https://lkml.kernel.org/n/tip-hpw7vdjp7g92ivgpddrp5ydq@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Grab a copy of the s390 system call table file introduced with commit
857f46bfb07f53dc112d69bdfb137cc5ec3da7c5 "s390/syscalls: add system call
table".

Signed-off-by: Hendrik Brueckner &lt;brueckner@linux.vnet.ibm.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Thomas Richter &lt;tmricht@linux.vnet.ibm.com&gt;
Cc: linux-s390@vger.kernel.org
LPU-Reference: 1518090470-2899-3-git-send-email-brueckner@linux.vnet.ibm.com
Link: https://lkml.kernel.org/n/tip-hpw7vdjp7g92ivgpddrp5ydq@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tools/headers: Synchronize kernel ABI headers, v4.16-rc1</title>
<updated>2018-02-15T13:01:46+00:00</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@kernel.org</email>
</author>
<published>2018-02-13T11:54:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f091f1d6a2b4840c9b631d6138f5354401347863'/>
<id>f091f1d6a2b4840c9b631d6138f5354401347863</id>
<content type='text'>
Sync the following tooling headers with the latest kernel version:

  tools/arch/powerpc/include/uapi/asm/kvm.h
  tools/arch/x86/include/asm/cpufeatures.h
  tools/include/uapi/drm/i915_drm.h
  tools/include/uapi/linux/if_link.h
  tools/include/uapi/linux/kvm.h

All the changes are new ABI additions which don't impact their use
in existing tooling.

Cc: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Sync the following tooling headers with the latest kernel version:

  tools/arch/powerpc/include/uapi/asm/kvm.h
  tools/arch/x86/include/asm/cpufeatures.h
  tools/include/uapi/drm/i915_drm.h
  tools/include/uapi/linux/if_link.h
  tools/include/uapi/linux/kvm.h

All the changes are new ABI additions which don't impact their use
in existing tooling.

Cc: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf test: Fix test trace+probe_libc_inet_pton.sh for s390x</title>
<updated>2018-02-15T12:57:47+00:00</updated>
<author>
<name>Thomas Richter</name>
<email>tmricht@linux.vnet.ibm.com</email>
</author>
<published>2018-01-17T08:38:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7a92453620d42c3a5fea94a864dc6aa04c262b93'/>
<id>7a92453620d42c3a5fea94a864dc6aa04c262b93</id>
<content type='text'>
On Intel test case trace+probe_libc_inet_pton.sh succeeds and the
output is:

[root@f27 perf]# ./perf trace --no-syscalls
                  -e probe_libc:inet_pton/max-stack=3/ ping -6 -c 1 ::1
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.037 ms

 --- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.037/0.037/0.037/0.000 ms
     0.000 probe_libc:inet_pton:(7fa40ac618a0))
              __GI___inet_pton (/usr/lib64/libc-2.26.so)
              getaddrinfo (/usr/lib64/libc-2.26.so)
              main (/usr/bin/ping)

The kernel stack unwinder is used, it is specified implicitly
as call-graph=fp (frame pointer).

On s390x only dwarf is available for stack unwinding. It is also
done in user space. This requires different parameter setup
and result checking for s390x and Intel.

This patch adds separate perf trace setup and result checking
for Intel and s390x. On s390x specify this command line to
get a call-graph and handle the different call graph result
checking:

[root@s35lp76 perf]# ./perf trace --no-syscalls
	-e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.041 ms

 --- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.041/0.041/0.041/0.000 ms
     0.000 probe_libc:inet_pton:(3ffb9942060))
            __GI___inet_pton (/usr/lib64/libc-2.26.so)
            gaih_inet (inlined)
            __GI_getaddrinfo (inlined)
            main (/usr/bin/ping)
            __libc_start_main (/usr/lib64/libc-2.26.so)
            _start (/usr/bin/ping)
[root@s35lp76 perf]#

Before:
[root@s8360047 perf]# ./perf test -vv 58
58: probe libc's inet_pton &amp; backtrace it with ping       :
 --- start ---
test child forked, pid 26349
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.079 ms
 --- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.079/0.079/0.079/0.000 ms
0.000 probe_libc:inet_pton:(3ff925c2060))
test child finished with -1
 ---- end ----
probe libc's inet_pton &amp; backtrace it with ping: FAILED!
[root@s8360047 perf]#

After:
[root@s35lp76 perf]# ./perf test -vv 57
57: probe libc's inet_pton &amp; backtrace it with ping       :
 --- start ---
test child forked, pid 38708
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.038 ms
 --- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.038/0.038/0.038/0.000 ms
0.000 probe_libc:inet_pton:(3ff87342060))
__GI___inet_pton (/usr/lib64/libc-2.26.so)
gaih_inet (inlined)
__GI_getaddrinfo (inlined)
main (/usr/bin/ping)
__libc_start_main (/usr/lib64/libc-2.26.so)
_start (/usr/bin/ping)
test child finished with 0
 ---- end ----
probe libc's inet_pton &amp; backtrace it with ping: Ok
[root@s35lp76 perf]#

On Intel the test case runs unchanged and succeeds.

Signed-off-by: Thomas Richter &lt;tmricht@linux.vnet.ibm.com&gt;
Reviewed-by: Hendrik Brueckner &lt;brueckner@linux.vnet.ibm.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Link: http://lkml.kernel.org/r/20180117083831.101001-1-tmricht@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
On Intel test case trace+probe_libc_inet_pton.sh succeeds and the
output is:

[root@f27 perf]# ./perf trace --no-syscalls
                  -e probe_libc:inet_pton/max-stack=3/ ping -6 -c 1 ::1
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.037 ms

 --- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.037/0.037/0.037/0.000 ms
     0.000 probe_libc:inet_pton:(7fa40ac618a0))
              __GI___inet_pton (/usr/lib64/libc-2.26.so)
              getaddrinfo (/usr/lib64/libc-2.26.so)
              main (/usr/bin/ping)

The kernel stack unwinder is used, it is specified implicitly
as call-graph=fp (frame pointer).

On s390x only dwarf is available for stack unwinding. It is also
done in user space. This requires different parameter setup
and result checking for s390x and Intel.

This patch adds separate perf trace setup and result checking
for Intel and s390x. On s390x specify this command line to
get a call-graph and handle the different call graph result
checking:

[root@s35lp76 perf]# ./perf trace --no-syscalls
	-e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.041 ms

 --- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.041/0.041/0.041/0.000 ms
     0.000 probe_libc:inet_pton:(3ffb9942060))
            __GI___inet_pton (/usr/lib64/libc-2.26.so)
            gaih_inet (inlined)
            __GI_getaddrinfo (inlined)
            main (/usr/bin/ping)
            __libc_start_main (/usr/lib64/libc-2.26.so)
            _start (/usr/bin/ping)
[root@s35lp76 perf]#

Before:
[root@s8360047 perf]# ./perf test -vv 58
58: probe libc's inet_pton &amp; backtrace it with ping       :
 --- start ---
test child forked, pid 26349
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.079 ms
 --- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.079/0.079/0.079/0.000 ms
0.000 probe_libc:inet_pton:(3ff925c2060))
test child finished with -1
 ---- end ----
probe libc's inet_pton &amp; backtrace it with ping: FAILED!
[root@s8360047 perf]#

After:
[root@s35lp76 perf]# ./perf test -vv 57
57: probe libc's inet_pton &amp; backtrace it with ping       :
 --- start ---
test child forked, pid 38708
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.038 ms
 --- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.038/0.038/0.038/0.000 ms
0.000 probe_libc:inet_pton:(3ff87342060))
__GI___inet_pton (/usr/lib64/libc-2.26.so)
gaih_inet (inlined)
__GI_getaddrinfo (inlined)
main (/usr/bin/ping)
__libc_start_main (/usr/lib64/libc-2.26.so)
_start (/usr/bin/ping)
test child finished with 0
 ---- end ----
probe libc's inet_pton &amp; backtrace it with ping: Ok
[root@s35lp76 perf]#

On Intel the test case runs unchanged and succeeds.

Signed-off-by: Thomas Richter &lt;tmricht@linux.vnet.ibm.com&gt;
Reviewed-by: Hendrik Brueckner &lt;brueckner@linux.vnet.ibm.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Link: http://lkml.kernel.org/r/20180117083831.101001-1-tmricht@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf data: Document missing --force option</title>
<updated>2018-02-15T12:57:33+00:00</updated>
<author>
<name>Sangwon Hong</name>
<email>qpakzk@gmail.com</email>
</author>
<published>2018-02-05T11:48:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ba7e851642f48002def3450b279598c187721fd0'/>
<id>ba7e851642f48002def3450b279598c187721fd0</id>
<content type='text'>
Add the --force option to the man page.

Signed-off-by: Sangwon Hong &lt;qpakzk@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Taeung Song &lt;treeze.taeung@gmail.com&gt;
Link: http://lkml.kernel.org/r/1517831315-31490-1-git-send-email-qpakzk@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add the --force option to the man page.

Signed-off-by: Sangwon Hong &lt;qpakzk@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Taeung Song &lt;treeze.taeung@gmail.com&gt;
Link: http://lkml.kernel.org/r/1517831315-31490-1-git-send-email-qpakzk@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Substitute yet another strtoull()</title>
<updated>2018-02-15T12:57:19+00:00</updated>
<author>
<name>Andy Shevchenko</name>
<email>andriy.shevchenko@linux.intel.com</email>
</author>
<published>2018-01-29T13:03:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6677d26c8befa462eab9be6c5335a939011e7e65'/>
<id>6677d26c8befa462eab9be6c5335a939011e7e65</id>
<content type='text'>
Instead of home grown function let's use what library provides us.

Signed-off-by: Andriy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: http://lkml.kernel.org/r/20180129130359.1490-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Instead of home grown function let's use what library provides us.

Signed-off-by: Andriy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: http://lkml.kernel.org/r/20180129130359.1490-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf top: Check the latency of perf_top__mmap_read()</title>
<updated>2018-02-15T12:57:06+00:00</updated>
<author>
<name>Kan Liang</name>
<email>kan.liang@intel.com</email>
</author>
<published>2018-01-18T21:26:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8cc42de736b617827a4e7664fb8d7a325bc125bc'/>
<id>8cc42de736b617827a4e7664fb8d7a325bc125bc</id>
<content type='text'>
The latency of perf_top__mmap_read() should be lower than refresh time.
If not, give some hints to reduce the latency.

Signed-off-by: Kan Liang &lt;kan.liang@intel.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: http://lkml.kernel.org/r/1516310792-208685-18-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The latency of perf_top__mmap_read() should be lower than refresh time.
If not, give some hints to reduce the latency.

Signed-off-by: Kan Liang &lt;kan.liang@intel.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: http://lkml.kernel.org/r/1516310792-208685-18-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf top: Switch default mode to overwrite mode</title>
<updated>2018-02-15T12:56:54+00:00</updated>
<author>
<name>Kan Liang</name>
<email>kan.liang@intel.com</email>
</author>
<published>2018-01-18T21:26:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ebebbf082357f86cc84a4d46ce897a5750e41b7a'/>
<id>ebebbf082357f86cc84a4d46ce897a5750e41b7a</id>
<content type='text'>
perf_top__mmap_read() has a severe performance issue in the Knights
Landing/Mill platform, when monitoring heavy load systems. It costs
several minutes to finish, which is unacceptable.

Currently, 'perf top' uses the non overwrite mode. For non overwrite
mode, it tries to read everything in the ringbuffer and doesn't pause
it. Once there are lots of samples delivered persistently, the
processing time could be very long. Also, the latest samples could be
lost when the ringbuffer is full.

For overwrite mode, it takes a snapshot for the system by pausing the
ringbuffer, which could significantly reduce the processing time.  Also,
the overwrite mode always keep the latest samples.  Considering the real
time requirement for 'perf top', the overwrite mode is more suitable for
it.

Actually, 'perf top' was overwrite mode. It is changed to non overwrite
mode since commit 93fc64f14472 ("perf top: Switch to non overwrite
mode"). It's better to change it back to overwrite mode by default.

For the kernel which doesn't support overwrite mode, it will fall back
to non overwrite mode.

There would be some records lost in overwrite mode because of pausing
the ringbuffer. It has little impact for the accuracy of the snapshot
and can be tolerated.

For overwrite mode, unconditionally wait 100 ms before each snapshot. It
also reduces the overhead caused by pausing ringbuffer, especially on
light load system.

Signed-off-by: Kan Liang &lt;kan.liang@intel.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: http://lkml.kernel.org/r/1516310792-208685-17-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
perf_top__mmap_read() has a severe performance issue in the Knights
Landing/Mill platform, when monitoring heavy load systems. It costs
several minutes to finish, which is unacceptable.

Currently, 'perf top' uses the non overwrite mode. For non overwrite
mode, it tries to read everything in the ringbuffer and doesn't pause
it. Once there are lots of samples delivered persistently, the
processing time could be very long. Also, the latest samples could be
lost when the ringbuffer is full.

For overwrite mode, it takes a snapshot for the system by pausing the
ringbuffer, which could significantly reduce the processing time.  Also,
the overwrite mode always keep the latest samples.  Considering the real
time requirement for 'perf top', the overwrite mode is more suitable for
it.

Actually, 'perf top' was overwrite mode. It is changed to non overwrite
mode since commit 93fc64f14472 ("perf top: Switch to non overwrite
mode"). It's better to change it back to overwrite mode by default.

For the kernel which doesn't support overwrite mode, it will fall back
to non overwrite mode.

There would be some records lost in overwrite mode because of pausing
the ringbuffer. It has little impact for the accuracy of the snapshot
and can be tolerated.

For overwrite mode, unconditionally wait 100 ms before each snapshot. It
also reduces the overhead caused by pausing ringbuffer, especially on
light load system.

Signed-off-by: Kan Liang &lt;kan.liang@intel.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: http://lkml.kernel.org/r/1516310792-208685-17-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
