In perf_mmap__read(), give better names to pointers. Original name 'old'
and 'head' directly related to pointers in ring buffer control page. For
backward ring buffer, the meaning of 'head' point is not 'the first byte
of free space', but 'the first byte of the last record'. To reduce
confusion, rename 'old' to 'start', 'head' to 'end'. 'start' -> 'end'
is the direction the records should be read from.
Change parameter order.
Change 'overwrite' to 'check_messup'. When reading from 'head', no need
to check messup for for backward ring buffer.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1461723563-67451-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Don't read broken data after 'head' pointer.
Following commits will feed perf_evlist__mmap_read() with some 'head'
pointers not maintained by kernel. If 'head' pointer breaks an event, we
should avoid reading from the broken event. This can happen in backward
ring buffer.
For example:
old head
| |
V V
+---+------+----------+----+-----+--+
|..E|D....D|C........C|B..B|A....|E.|
+---+------+----------+----+-----+--+
'old' pointer points to the beginning of 'A' and trying read from it,
but 'A' has been overwritten. In this case, don't try to read from 'A',
simply return NULL.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1461637738-62722-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When running the "code reading" test we get:
# perf test -v "code reading" 2>&1 | tail -5
Parsing event 'cycles:u'
perf_evlist__open failed
test child finished with -1
---- end ----
Test object code reading: FAILED!
#
And with -vv we get the errno value, -22, i.e. -EINVAL, but we can do
better and handle the case at hand, with this patch it becomes:
# perf test -v "code reading" 2>&1 | tail -7
perf_evlist__open() failed!
Error: Invalid argument.
Hint: Check /proc/sys/kernel/perf_event_max_sample_rate.
Hint: The current value is 1000 and 4000 is being requested.
test child finished with -1
---- end ----
Test object code reading: FAILED!
#
Next patch will make this 'perf test' entry to use perf_evlist__strerror()
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Noonan <steven@uplinklabs.net>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-i31ai6kfefn75eapejjokfhc@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We were dropping the reference we possibly held but not obtaining one
for the new maps, which we will drop at perf_evlist__delete(), fix it.
This was caught by Steven Noonan in some of the machines which would
produce this output when caught by glibc debug mechanisms:
$ sudo perf test 21
21: Test object code reading :***
Error in `perf': corrupted double-linked list: 0x00000000023ffcd0 ***
======= Backtrace: =========
/usr/lib/libc.so.6(+0x72055)[0x7f25be0f3055]
/usr/lib/libc.so.6(+0x779b6)[0x7f25be0f89b6]
/usr/lib/libc.so.6(+0x7a0ed)[0x7f25be0fb0ed]
/usr/lib/libc.so.6(__libc_calloc+0xba)[0x7f25be0fceda]
perf(parse_events_lex_init_extra+0x38)[0x4cfff8]
perf(parse_events+0x55)[0x4a0615]
perf(perf_evlist__config+0xcf)[0x4eeb2f]
perf[0x479f82]
perf(test__code_reading+0x1e)[0x47ad4e]
perf(cmd_test+0x5dd)[0x46452d]
perf[0x47f4e3]
perf(main+0x603)[0x42c723]
/usr/lib/libc.so.6(__libc_start_main+0xf0)[0x7f25be0a1610]
perf(_start+0x29)[0x42c859]
Further investigation using valgrind led to the reference count imbalance fixed
in this patch.
Reported-and-Tested-by: Steven Noonan <steven@uplinklabs.net>
Report-Link: http://lkml.kernel.org/r/CAKbGBLjC2Dx5vshxyGmQkcD+VwiAQLbHoXA9i7kvRB2-2opHZQ@mail.gmail.com
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: f30a79b012 ("perf tools: Add reference counting for cpu_map object")
Link: http://lkml.kernel.org/n/tip-j0u1bdhr47sa511sgg76kb8h@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If the user doesn't specify any event, try the most precise "cycles"
available, i.e. start by "cycles:ppp" and go on removing "p" till it
works.
E.g.
$ perf record usleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.017 MB perf.data (11 samples) ]
$ perf evlist
cycles:pp
$ perf evlist -v
cycles:pp: size: 112, { sample_period, sample_freq }: 4000, sample_type:
IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1,
enable_on_exec: 1, task: 1, precise_ip: 2, sample_id_all: 1,
exclude_guest: 1, mmap2: 1, comm_exec: 1
$ grep 'model name' /proc/cpuinfo | head -1
model name : Intel(R) Core(TM) i7-3667U CPU @ 2.00GHz
$
When 'cycles' appears explicitely is specified this will not be tried,
i.e. the user has full control of the level of precision to be used:
$ perf record -e cycles usleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.016 MB perf.data (9 samples) ]
$ perf evlist
cycles
$ perf evlist -v
cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type:
IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1,
enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2:
1, comm_exec: 1
$
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Chandler Carruth <chandlerc@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://www.youtube.com/watch?v=nXaxk27zwlk
Link: http://lkml.kernel.org/n/tip-b1ywebmt22pi78vjxau01wth@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The validation checks that the values that were just assigned, got
assigned i.e. the error can't ever happen. Subsequent patches will call
this code in places where errors are not being returned. Changing those
code paths to return this non-existent error is counter-productive, so
just remove it.
That in turn results in perf_evlist__set_maps not needing to return an
error, but callers aren't checking it either, so remove that too.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Link: http://lkml.kernel.org/r/1441699142-18905-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Propagate error info from tp_format via ERR_PTR to get it all the way
down to the parse-event.c tracepoint adding routines. Following
functions now return pointer with encoded error:
- tp_format
- trace_event__tp_format
- perf_evsel__newtp_idx
- perf_evsel__newtp
This affects several other places in perf, that cannot use pointer check
anymore, but must utilize the err.h interface, when getting error
information from above functions list.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Raphael Beamonte <raphael.beamonte@gmail.com>
Link: http://lkml.kernel.org/r/1441615087-13886-5-git-send-email-jolsa@kernel.org
[ Add two missing ERR_PTR() and one IS_ERR() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Patch "perf script: Don't assume evsel position of tracking events"
changed 'perf script' to use 'perf_evlist__id2evsel()'. That results
in a segfault if there is more than 1 event and there are
synthesized mmap events e.g.
$ perf record -e cycles,instructions -p$$ sleep 1
$ perf script --show-mmap-events
Segmentation fault (core dumped)
That happens because these synthesized events have an 'id' of zero
which does not match any 'evsel'.
Currently, these synthesized events use the sample type of the first
evsel.
Change 'perf_evlist__id2evsel()' to reflect that which also makes
it consistent with 'perf_evlist__event2evsel()'.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Fixes: 06b234ec26 ("perf script: Don't assume evsel position of tracking events")
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1440059205-1765-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Instead of calling perf_evsel__apply_filter straight away, so that
we can, in the next patches, expand the filter with more conditions
before actually calling the ioctl to pass the end result filter to
the kernel.
Now we need to call perf_evlist__apply_filters() after the filter
is completely setup, i.e. do the ioctl calls.
The perf_evlist__apply_filters() method was already in place, because
that is the model for the other tools that receives filters in the
command line: go on setting then in the evsel->filter and only at
the end, after parsing the whole command line, apply them.
We get, as a bonus, a more expressive message that states which
event, if any, failed to have the filter applied to, with an
error message stating what happened.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-f429pgz75ryz7tpe6v74etre@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We need to be able to go on constructing a complex filter in multiple
stages, since we can only set one filter per event.
For instance, we need to be able, in 'perf trace' to filter by the
'common_pid' field all the time, if only for the tracer itself, to
avoid a feedback loop, and, in addition, we may want to filter the
raw_syscalls:sys_{enter,exit} events by its 'id' filter, when using
'perf trace -e open,close' or 'perf trace -e !open,close', i.e. when
we are interested in just a subset of syscalls or when we are not
interested in it.
So we will have:
perf_evsel__set_filter(evsel, char *filter)
Replaces whatever is in evsel->filter.
perf_evsel__append_filter(evsel, const char *op, char *filter)
Appends, using op ("&&" or "||") with what is in evsel->filter.
perf_evsel__apply_filter(evsel, filter):
That actually applies a filter, be it the one being
constructed in evsel->filter, or any other, for tools
with more specific ways to build the filter, issuing
the appropriate ioctl for all the evsel fds.
The same changes will be made to the evlist__{set,apply} variants to
keep everything consistent.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-2s5z9xtpnc2lwio3cv5x0jek@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
