linux-toradex.git/tools/perf/util/event.c, branch v3.2.9

perf symbols: Synthesize anonymous mmap events

2011-09-23T17:37:06+00:00

perf_event__synthesize_mmap_events does not create anonymous mmap events
even though the kernel does. As a result an already running application
with dynamically created code will not get profiled - all samples end up
in the unknown bucket.

This patch skips any entries with '[' in the name to avoid adding events
for special regions (eg the vsyscall page). All other executable mmaps
are assumed to be anonymous and an event is synthesized.

Acked-by: Pekka Enberg 
Cc: Eric B Munson 
Cc: Ingo Molnar 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Pekka Enberg 
Link: http://lkml.kernel.org/r/20110830091506.60b51fe8@kryten
Signed-off-by: Anton Blanchard 
Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Don't die if sample_{id_all|type} is invalid

2011-06-03T13:07:52+00:00

Fixes two more cases where the python binding would not load:

. Not finding die(), which it shouldn't anyway, not good to just stop the
  world because some particular perf.data file is invalid, just propagate
  the error to the caller.

. Not finding perf_sample_size: fix it by moving it from event.c to evsel,
  where it belongs, as most cases are moving to operate on an evsel object.o

One of the fixed problems:

[root@emilia ~]# python
>>> import perf
Traceback (most recent call last):
  File "", line 1, in 
ImportError: /home/acme/git/build/perf/python/perf.so: undefined symbol: perf_sample_size
>>>
[root@emilia ~]#

Cc: Frederic Weisbecker 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-1hkj7b2cvgbfnoizsekjb6c9@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Handle /proc/sys/kernel/kptr_restrict

2011-05-26T14:15:25+00:00

Perf uses /proc/modules to figure out where kernel modules are loaded.

With the advent of kptr_restrict, non root users get zeroes for all module
start addresses.

So check if kptr_restrict is non zero and don't generate the syntethic
PERF_RECORD_MMAP events for them.

Warn the user about it in perf record and in perf report.

In perf report the reference relocation symbol being zero means that
kptr_restrict was set, thus /proc/kallsyms has only zeroed addresses, so don't
use it to fixup symbol addresses when using a valid kallsyms (in the buildid
cache) or vmlinux (in the vmlinux path) build-id located automatically or
specified by the user.

Provide an explanation about it in 'perf report' if kernel samples were taken,
checking if a suitable vmlinux or kallsyms was found/specified.

Restricted /proc/kallsyms don't go to the buildid cache anymore.

Example:

 [acme@emilia ~]$ perf record -F 100000 sleep 1

 WARNING: Kernel address maps (/proc/{kallsyms,modules}) are restricted, check
 /proc/sys/kernel/kptr_restrict.

 Samples in kernel functions may not be resolved if a suitable vmlinux file is
 not found in the buildid cache or in the vmlinux path.

 Samples in kernel modules won't be resolved at all.

 If some relocation was applied (e.g. kexec) symbols may be misresolved even
 with a suitable vmlinux or kallsyms file.

 [ perf record: Woken up 1 times to write data ]
 [ perf record: Captured and wrote 0.005 MB perf.data (~231 samples) ]
 [acme@emilia ~]$

 [acme@emilia ~]$ perf report --stdio
 Kernel address maps (/proc/{kallsyms,modules}) were restricted,
 check /proc/sys/kernel/kptr_restrict before running 'perf record'.

 If some relocation was applied (e.g. kexec) symbols may be misresolved.

 Samples in kernel modules can't be resolved as well.

 # Events: 13  cycles
 #
 # Overhead  Command      Shared Object                 Symbol
 # ........  .......  .................  .....................
 #
    20.24%    sleep  [kernel.kallsyms]  [k] page_fault
    20.04%    sleep  [kernel.kallsyms]  [k] filemap_fault
    19.78%    sleep  [kernel.kallsyms]  [k] __lru_cache_add
    19.69%    sleep  ld-2.12.so         [.] memcpy
    14.71%    sleep  [kernel.kallsyms]  [k] dput
     4.70%    sleep  [kernel.kallsyms]  [k] flush_signal_handlers
     0.73%    sleep  [kernel.kallsyms]  [k] perf_event_comm
     0.11%    sleep  [kernel.kallsyms]  [k] native_write_msr_safe

 #
 # (For a higher level overview, try: perf report --sort comm,dso)
 #
 [acme@emilia ~]$

This is because it found a suitable vmlinux (build-id checked) in
/lib/modules/2.6.39-rc7+/build/vmlinux (use -v in perf report to see the long
file name).

If we remove that file from the vmlinux path:

 [root@emilia ~]# mv /lib/modules/2.6.39-rc7+/build/vmlinux \
		     /lib/modules/2.6.39-rc7+/build/vmlinux.OFF
 [acme@emilia ~]$ perf report --stdio
 [kernel.kallsyms] with build id 57298cdbe0131f6871667ec0eaab4804dcf6f562
 not found, continuing without symbols

 Kernel address maps (/proc/{kallsyms,modules}) were restricted, check
 /proc/sys/kernel/kptr_restrict before running 'perf record'.

 As no suitable kallsyms nor vmlinux was found, kernel samples can't be
 resolved.

 Samples in kernel modules can't be resolved as well.

 # Events: 13  cycles
 #
 # Overhead  Command      Shared Object  Symbol
 # ........  .......  .................  ......
 #
    80.31%    sleep  [kernel.kallsyms]  [k] 0xffffffff8103425a
    19.69%    sleep  ld-2.12.so         [.] memcpy

 #
 # (For a higher level overview, try: perf report --sort comm,dso)
 #
 [acme@emilia ~]$

Reported-by: Stephane Eranian 
Suggested-by: David Miller 
Cc: Dave Jones 
Cc: David Miller 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Kees Cook 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Pekka Enberg 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Tom Zanussi 
Link: http://lkml.kernel.org/n/tip-mt512joaxxbhhp1odop04yit@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix sample type size calculation in 32 bits archs

2011-05-24T02:33:24+00:00

The shift used here to count the number of bits set in
the mask doesn't work above the low part for archs that
are not 64 bits.

Fix the constant used for the shift.

This fixes a 32-bit perf top failure reported by Eric Dumazet:

	Can't parse sample, err = -14
	Can't parse sample, err = -14
	...

Reported-and-tested-by: Eric Dumazet 
Signed-off-by: Frederic Weisbecker 
Cc: Linus Torvalds 
Cc: Steven Rostedt 
Cc: Eric Dumazet 
Cc: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Stephane Eranian

perf tools: Fix sample size bit operations

2011-05-23T11:26:36+00:00

What we want is to count the number of bits in the mask,
not some other random operation written in the middle
of the night.

Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1306148788-6179-2-git-send-email-fweisbec@gmail.com
[ Fixed perf_event__names[] alignment which was nearby and hurting my eyes ... ]
Signed-off-by: Ingo Molnar

perf tools: Pre-check sample size before parsing

2011-05-22T01:38:36+00:00

Check that the total size of the sample fields having a fixed
size do not exceed the one of the whole event. This robustifies
the sample parsing.

Signed-off-by: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Stephane Eranian

perf symbols: Fix vsyscall symbol lookup

2011-03-28T17:44:15+00:00

Perf can't currently trace into the vsyscall page.  It looks like it was
meant to work.

Tested on 2.6.38 and today's -git.

The bug is easy to reproduce.  Compile this:

int main()
{
	int i;
	struct timespec t;
	for(i = 0; i < 10000000; i++)
		clock_gettime(CLOCK_MONOTONIC, &t);
	return 0;
}

and run it through perf record; perf report.  The top entry shows
"[unknown]" and you can't zoom in.

It looks like there are two issues.  The first is a that a test for user
mode executing in kernel space is backwards.  (That's the first hunk
below).  The second (I think) is that something's wrong with the code
that generates lots of little struct dso objects for different sections
-- when it runs on vmlinux it results in bogus long_name values which
cause objdump to fail.

Cc: Ingo Molnar 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
LPU-Reference: 
Signed-off-by: Andy Lutomirski 
Signed-off-by: Arnaldo Carvalho de Melo

perf hists: Remove needless global col lenght calcs

2011-03-06T01:31:04+00:00

To support multiple events we need to do these calcs per 'struct hists'
instance, and it turns out we already do that at:

	__hists__add_entry
		hists__inc_nr_entries
			hists__calc_col_len

for all the unfiltered hist_entry instances we stash in the rb tree, so
trow away the dead code.

Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Tom Zanussi 
LKML-Reference: 
Signed-off-by: Arnaldo Carvalho de Melo

Merge remote branch 'acme/perf/urgent' into perf/core

2011-02-11T13:45:54+00:00

Fixups due to rename of event_t routines from event__ to perf_event__
done in perf/core.

Conflicts:
	tools/perf/builtin-record.c
	tools/perf/builtin-top.c
	tools/perf/util/event.c
	tools/perf/util/event.h

Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix thread_map event synthesizing in top and record

2011-02-10T14:52:47+00:00

Jeff Moyer reported these messages:

  Warning:  ... trying to fall back to cpu-clock-ticks

couldn't open /proc/-1/status
couldn't open /proc/-1/maps
[ls output]
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.008 MB perf.data (~363 samples) ]

That lead me and David Ahern to see that something was fishy on the thread
synthesizing routines, at least for the case where the workload is started
from 'perf record', as -1 is the default for target_tid in 'perf record --tid'
parameter, so somehow we were trying to synthesize the PERF_RECORD_MMAP and
PERF_RECORD_COMM events for the thread -1, a bug.

So I investigated this and noticed that when we introduced support for
recording a process and its threads using --pid some bugs were introduced and
that the way to fix it was to instead of passing the target_tid to the event
synthesizing routines we should better pass the thread_map that has the list of
threads for a --pid or just the single thread for a --tid.

Checked in the following ways:

On a 8-way machine run cyclictest:

[root@emilia ~]# perf record cyclictest -a -t -n -p99 -i100 -d50
policy: fifo: loadavg: 0.00 0.13 0.31 2/139 28798

T: 0 (28791) P:99 I:100 C:  25072 Min:      4 Act:    5 Avg:    6 Max:     122
T: 1 (28792) P:98 I:150 C:  16715 Min:      4 Act:    6 Avg:    5 Max:      27
T: 2 (28793) P:97 I:200 C:  12534 Min:      4 Act:    5 Avg:    4 Max:       8
T: 3 (28794) P:96 I:250 C:  10028 Min:      4 Act:    5 Avg:    5 Max:      96
T: 4 (28795) P:95 I:300 C:   8357 Min:      5 Act:    6 Avg:    5 Max:      12
T: 5 (28796) P:94 I:350 C:   7163 Min:      5 Act:    6 Avg:    5 Max:      12
T: 6 (28797) P:93 I:400 C:   6267 Min:      4 Act:    5 Avg:    5 Max:       9
T: 7 (28798) P:92 I:450 C:   5571 Min:      4 Act:    5 Avg:    5 Max:       9
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.108 MB perf.data (~4719 samples) ]

[root@emilia ~]#

This will create one extra thread per CPU:

[root@emilia ~]# tuna -t cyclictest -CP
                      thread       ctxt_switches
    pid SCHED_ rtpri affinity voluntary nonvoluntary             cmd
 28825   OTHER     0     0xff      2169          671      cyclictest
  28832   FIFO    93        6     52338            1      cyclictest
  28833   FIFO    92        7     46524            1      cyclictest
  28826   FIFO    99        0    209360            1      cyclictest
  28827   FIFO    98        1    139577            1      cyclictest
  28828   FIFO    97        2    104686            0      cyclictest
  28829   FIFO    96        3     83751            1      cyclictest
  28830   FIFO    95        4     69794            1      cyclictest
  28831   FIFO    94        5     59825            1      cyclictest
[root@emilia ~]#

So we should expect only samples for the above 9 threads when using the
--dump-raw-trace|-D perf report switch to look at the column with the tid:

[root@emilia ~]# perf report -D | grep RECORD_SAMPLE | cut -d/ -f2 | cut -d: -f1 | sort | uniq -c
    629 28825
    110 28826
    491 28827
    308 28828
    198 28829
    621 28830
    225 28831
    203 28832
     89 28833
[root@emilia ~]#

So for workloads started by 'perf record' seems to work, now for existing workloads,
just run cyclictest first, without 'perf record':

[root@emilia ~]# tuna -t cyclictest -CP
                      thread       ctxt_switches
    pid SCHED_ rtpri affinity voluntary nonvoluntary             cmd
 28859   OTHER     0     0xff       594          200      cyclictest
  28864   FIFO    95        4     16587            1      cyclictest
  28865   FIFO    94        5     14219            1      cyclictest
  28866   FIFO    93        6     12443            0      cyclictest
  28867   FIFO    92        7     11062            1      cyclictest
  28860   FIFO    99        0     49779            1      cyclictest
  28861   FIFO    98        1     33190            1      cyclictest
  28862   FIFO    97        2     24895            1      cyclictest
  28863   FIFO    96        3     19918            1      cyclictest
[root@emilia ~]#

and then later did:

[root@emilia ~]# perf record --pid 28859 sleep 3
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.027 MB perf.data (~1195 samples) ]
[root@emilia ~]#

To collect 3 seconds worth of samples for pid 28859 and its children:

[root@emilia ~]# perf report -D | grep RECORD_SAMPLE | cut -d/ -f2 | cut -d: -f1 | sort | uniq -c
     15 28859
     33 28860
     19 28861
     13 28862
     13 28863
     10 28864
     11 28865
      9 28866
    255 28867
[root@emilia ~]#

Works, last thing is to check if looking at just one of those threads also works:

[root@emilia ~]# perf record --tid 28866 sleep 3
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.006 MB perf.data (~242 samples) ]
[root@emilia ~]# perf report -D | grep RECORD_SAMPLE | cut -d/ -f2 | cut -d: -f1 | sort | uniq -c
      3 28866
[root@emilia ~]#

Works too.

Reported-by: Jeff Moyer 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Jeff Moyer 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Tom Zanussi 
LKML-Reference: 
Signed-off-by: Arnaldo Carvalho de Melo