linux.git/tools/perf, branch v4.16-rc4

tools: fix cross-compile var clobbering

2018-02-21T23:35:42+00:00

Currently a number of Makefiles break when used with toolchains that
pass extra flags in CC and other cross-compile related variables (such
as --sysroot).

Thus we get this error when we use a toolchain that puts --sysroot in
the CC var:

  ~/src/linux/tools$ make iio
  [snip]
  iio_event_monitor.c:18:10: fatal error: unistd.h: No such file or directory
    #include 
             ^~~~~~~~~~

This occurs because we clobber several env vars related to
cross-compiling with lines like this:

  CC = $(CROSS_COMPILE)gcc

Although this will point to a valid cross-compiler, we lose any extra
flags that might exist in the CC variable, which can break toolchains
that rely on them (for example, those that use --sysroot).

This easily shows up using a Yocto SDK:

  $ . [snip]/sdk/environment-setup-cortexa8hf-neon-poky-linux-gnueabi

  $ echo $CC
  arm-poky-linux-gnueabi-gcc -march=armv7-a -mfpu=neon -mfloat-abi=hard
  -mcpu=cortex-a8
  --sysroot=[snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi

  $ echo $CROSS_COMPILE
  arm-poky-linux-gnueabi-

  $ echo ${CROSS_COMPILE}gcc
  krm-poky-linux-gnueabi-gcc

Although arm-poky-linux-gnueabi-gcc is a cross-compiler, we've lost the
--sysroot and other flags that enable us to find the right libraries to
link against, so we can't find unistd.h and other libraries and headers.
Normally with the --sysroot flag we would find unistd.h in the sdk
directory in the sysroot:

  $ find [snip]/sdk/sysroots -path '*/usr/include/unistd.h'
  [snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi/usr/include/unistd.h

The perf Makefile adds CC = $(CROSS_COMPILE)gcc if and only if CC is not
already set, and it compiles correctly with the above toolchain.

So, generalize the logic that perf uses in the common Makefile and
remove the manual CC = $(CROSS_COMPILE)gcc lines from each Makefile.

Note that this patch does not fix cross-compile for all the tools (some
have other bugs), but it does fix it for all except usb and acpi, which
still have other unrelated issues.

I tested both with and without the patch on native and cross-build and
there appear to be no regressions.

Link: http://lkml.kernel.org/r/20180107214028.23771-1-martin@martingkelly.com
Signed-off-by: Martin Kelly 
Acked-by: Mark Brown 
Cc: Tejun Heo 
Cc: Li Zefan 
Cc: Johannes Weiner 
Cc: Linus Walleij 
Cc: "K. Y. Srinivasan" 
Cc: Haiyang Zhang 
Cc: Stephen Hemminger 
Cc: Jonathan Cameron 
Cc: Pali Rohar 
Cc: Richard Purdie 
Cc: Jacek Anaszewski 
Cc: Pavel Machek 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Arnaldo Carvalho de Melo 
Cc: Robert Moore 
Cc: Lv Zheng 
Cc: "Rafael J. Wysocki" 
Cc: Greg Kroah-Hartman 
Cc: Valentina Manea 
Cc: Shuah Khan 
Cc: Mario Limonciello 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Revert "tools include s390: Grab a copy of arch/s390/include/uapi/asm/unistd.h"

2018-02-15T13:06:15+00:00

This reverts commit f120c7b187e6c418238710b48723ce141f467543 which is no
longer required with the introduction of a syscall.tbl on s390.

Signed-off-by: Hendrik Brueckner 
Cc: Jiri Olsa 
Cc: Michael Petlan 
Cc: Thomas Richter 
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

perf s390: Rework system call table creation by using syscall.tbl

2018-02-15T13:06:08+00:00

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 
Cc: Jiri Olsa 
Cc: Michael Petlan 
Cc: Thomas Richter 
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

perf s390: Grab a copy of arch/s390/kernel/syscall/syscall.tbl

2018-02-15T13:06:00+00:00

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 
Cc: Jiri Olsa 
Cc: Michael Petlan 
Cc: Thomas Richter 
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

perf test: Fix test trace+probe_libc_inet_pton.sh for s390x

2018-02-15T12:57:47+00:00

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 & 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 & backtrace it with ping: FAILED!
[root@s8360047 perf]#

After:
[root@s35lp76 perf]# ./perf test -vv 57
57: probe libc's inet_pton & 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 & backtrace it with ping: Ok
[root@s35lp76 perf]#

On Intel the test case runs unchanged and succeeds.

Signed-off-by: Thomas Richter 
Reviewed-by: Hendrik Brueckner 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Heiko Carstens 
Cc: Martin Schwidefsky 
Link: http://lkml.kernel.org/r/20180117083831.101001-1-tmricht@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf data: Document missing --force option

2018-02-15T12:57:33+00:00

Add the --force option to the man page.

Signed-off-by: Sangwon Hong 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Taeung Song 
Link: http://lkml.kernel.org/r/1517831315-31490-1-git-send-email-qpakzk@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Substitute yet another strtoull()

2018-02-15T12:57:19+00:00

Instead of home grown function let's use what library provides us.

Signed-off-by: Andriy Shevchenko 
Acked-by: Jiri Olsa 
Link: http://lkml.kernel.org/r/20180129130359.1490-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf top: Check the latency of perf_top__mmap_read()

2018-02-15T12:57:06+00:00

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 
Acked-by: Jiri Olsa 
Cc: Andi Kleen 
Cc: Jin Yao 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/1516310792-208685-18-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf top: Switch default mode to overwrite mode

2018-02-15T12:56:54+00:00

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 
Acked-by: Jiri Olsa 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Andi Kleen 
Cc: Jin Yao 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/1516310792-208685-17-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf top: Remove lost events checking

2018-02-15T12:56:43+00:00

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 could be tolerated by 'perf top'.

Remove the lost events checking.

Signed-off-by: Kan Liang 
Acked-by: Jiri Olsa 
Cc: Andi Kleen 
Cc: Jin Yao 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/1516310792-208685-16-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo