To fully annotate BPF programs with source code mapping, 4 different
information are needed:
1) PERF_RECORD_KSYMBOL
2) PERF_RECORD_BPF_EVENT
3) bpf_prog_info
4) btf
This patch handles 3) and 4) for BPF programs loaded after 'perf
record|top'.
For timely process of these information, a dedicated event is added to
the side band evlist.
When PERF_RECORD_BPF_EVENT is received via the side band event, the
polling thread gathers 3) and 4) vis sys_bpf and store them in perf_env.
This information is saved to perf.data at the end of 'perf record'.
Committer testing:
The 'wakeup_watermark' member in 'struct perf_event_attr' is inside a
unnamed union, so can't be used in a struct designated initialization
with older gccs, get it out of that, isolating as 'attr.wakeup_watermark
= 1;' to work with all gcc versions.
We also need to add '--no-bpf-event' to the 'perf record'
perf_event_attr tests in 'perf test', as the way that that test goes is
to intercept the events being setup and looking if they match the fields
described in the control files, since now it finds first the side band
event used to catch the PERF_RECORD_BPF_EVENT, they all fail.
With these issues fixed:
Same scenario as for testing BPF programs loaded before 'perf record' or
'perf top' starts, only start the BPF programs after 'perf record|top',
so that its information get collected by the sideband threads, the rest
works as for the programs loaded before start monitoring.
Add missing 'inline' to the bpf_event__add_sb_event() when
HAVE_LIBBPF_SUPPORT is not defined, fixing the build in systems without
binutils devel files installed.
Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <sdf@google.com>
Link: http://lkml.kernel.org/r/20190312053051.2690567-16-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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 <songliubraving@fb.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <sdf@google.com>
Link: http://lkml.kernel.org/r/20190312053051.2690567-15-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
At the cost of an extra pointer, we can avoid the O(logN) cost of
finding the first element in the tree (smallest node), which is
something heavily required for histograms. Specifically, the following
are converted to rb_root_cached, and users accordingly:
hist::entries_in_array
hist::entries_in
hist::entries
hist::entries_collapsed
hist_entry::hroot_in
hist_entry::hroot_out
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20181206191819.30182-7-dave@stgolabs.net
[ Added some missing conversions to rb_first_cached() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This restriction is not present in 'perf report' and since 'perf top'
uses the same hists browser, remove it from it as well.
With this we create per event buckets with callchain trees, so that
# perf top --sort dso -g --no-children
Bucketizes samples by DSO and below it shows the callchains leading to
functions in this DSO.
Try also:
# perf top -e sched:*switch -g --no-children
To see the callchains leading to sched switches, pressing 'E' to expand
all one can quickly see the most common scheduler switches and what
leads to them, for instance, calls to IO, futexes, etc.
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: https://lkml.kernel.org/r/20190107140854.GA28965@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Use conditional variable logic to synchronize between the reading and
processing threads. Currently it's done by having mutex around rotation
code.
Using a POSIX cond variable to sync both threads after queues rotation:
Process thread:
- Detects data
- Switches queues
- Sets rotate variable
- Waits in pthread_cond_wait()
Read thread:
- Detects rotate is set
- Kicks the process thread with a pthread_cond_signal()
After this rotation is safely completed and both threads can continue
with the new queue.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-3rdeg23rv3brvy1pwt3igvyw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add a new thread that takes care of the hist creating to alleviate the
main reader thread so it can keep perf mmaps served in time so that we
reduce the possibility of losing events.
The 'perf top' command now spawns 2 extra threads, the data processing
is the following:
1) The main thread reads the data from mmaps and queues them to
ordered events object;
2) The processing threads takes the data from the ordered events
object and create initial histogram;
3) The GUI thread periodically sorts the initial histogram and
presents it.
Passing the data between threads 1 and 2 is done by having 2 ordered
events queues. One is always being stored by thread 1 while the other is
flushed out in thread 2.
Passing the data between threads 2 and 3 stays the same as was initially
for threads 1 and 3.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-hhf4hllgkmle9wl1aly1jli0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Go over the tools/ files that are maintained in Arnaldo's tree and
fix common typos: half of them were in comments, the other half
in JSON files.
No change in functionality intended.
Committer notes:
This was split from a larger patch as there are code that is,
additionally, maintained outside the kernel tree, so to ease
cherry-picking and/or backporting, split this into multiple patches.
Just typos in comments, no need to backport, reducing the possibility of
possible backporting artifacts.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20181203102200.GA104797@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If events are coming in at a rate such that the event processing thread
can barely keep up, our initial run of the event ring will almost never
terminate and this delays the starting of the display thread.
The screen basically stays black until the event thread can get out of
it's endless loop.
Therefore, start the display thread before we start processing the ring
buffer.
This also make sure that we always have the user requested real time
setting engaged when processing the ring.
Signed-off-by: David S. Miller <davem@davemloft.net>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20181030.223003.2242527041807905962.davem@davemloft.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Enabling --overwrite mode allows us to to use just the most recent
records, which helps in high core count machines such as Knights
Landing/Mill, but right now is being disabled by default as the pausing
used in this technique is leading to loss of metadata events such as
PERF_RECORD_MMAP which makes 'perf top' unable to resolve samples,
leading to lots of unknown samples appearing on the UI.
Enabling this may be useful if you are in such machines and profiling a
workload that doesn't creates short lived threads and/or doesn't uses
many executable mmap operations.
Work is being planed to solve this situation, till then, this will
remain disabled by default.
Reported-by: David Miller <davem@davemloft.net>
Acked-by: Kan Liang <kan.liang@intel.com>
Link: https://lkml.kernel.org/r/4f84468f-37d9-cf1b-12c1-514ef74b6a48@linux.intel.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: ebebbf0823 ("perf top: Switch default mode to overwrite mode")
Link: https://lkml.kernel.org/n/tip-ehvf77vi1si9409r7p4wx788@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In ebebbf0823 ("perf top: Switch default mode to overwrite mode") we
forgot to leave a way to disable that new default, add a --overwrite
option that can be disabled using --no-overwrite, since the code already
in such a way that we can readily disable this mode.
This is useful when investigating bugs with this mode like the recent
report from David Miller where lots of unknown symbols appear due to
disabling the events while processing them which disables all record
types, not just PERF_RECORD_SAMPLE, which makes it impossible to resolve
maps when we lose PERF_RECORD_MMAP records.
This can be easily seen while building a kernel, when there are lots of
short lived processes.
Reported-by: David Miller <davem@davemloft.net>
Acked-by: Kan Liang <kan.liang@intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: ebebbf0823 ("perf top: Switch default mode to overwrite mode")
Link: https://lkml.kernel.org/n/tip-oqgsz2bq4kgrnnajrafcdhie@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
On older (e.g. v4.4) kernels, an annoying fallback message can be
observed in 'perf top':
┌─Warning:──────────────────────┐
│fall back to non-overwrite mode│
│ │
│ │
│Press any key... │
└───────────────────────────────┘
The 'perf top' utility has been changed to overwrite mode since commit
ebebbf0823 ("perf top: Switch default mode to overwrite mode").
For older kernels which don't have overwrite mode support, 'perf top'
will fall back to non-overwrite mode and print out the fallback message
using ui__warning(), which needs user's input to close.
The fallback message is not critical for end users. Turning it to debug
message which is printed when running with -vv.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Kan Liang <kan.liang@intel.com>
Fixes: ebebbf0823 ("perf top: Switch default mode to overwrite mode")
Link: http://lkml.kernel.org/r/1519669030-176549-1-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
