On Thu, Jun 24, 2021 at 05:43:02PM +0100, James Clark wrote:
Populate the auxtrace queues using AUX records rather than whole auxtrace buffers so that the decoder is reset between each aux record.
[...]
Signed-off-by: James Clark james.clark@arm.com
I tested this patch with kprobe/uprobe events; and confirmed this patch works as expected. So:
Tested-by: Leo Yan leo.yan@linaro.org
Below shares my testing steps.
- The rationale for the testing is to use "perf probe" to add trace points for PERF_RECORD_AUX/PERF_RECORD_AUXTRACE, and add another uprobe event for parsing AUX fragment. So we can compare the recorded PERF_RECORD_AUX events, and check if AUX fragment can reorganize the perf AUX trace data correctly or not.
- The testing script test_cs_etm_snapshot.sh: http://paste.debian.net/1202563/
- Add kprobe event for perf_event_aux_event() so that it can trace the perf event PERF_RECORD_AUX:
# perf probe --add "perf_event_aux_event head=head:x64 size=size:x64"
- Add uprobe event for __auxtrace_mmap__read() so that it can trace the perf event PERF_RECORD_AUXTRACE:
# perf probe -x /mnt/linux-kernel/linux-cs-dev/tools/perf/perf \ --add "__auxtrace_mmap__read:58 idx=mm->idx head=head:x64 offset=offset:x64 size=size:x64"
- Add uprobe event for cs_etm__queue_aux_fragment():
# perf probe -x /mnt/linux-kernel/linux-cs-dev/tools/perf/perf \ --add "cs_etm__queue_aux_fragment:63 aux_offset=aux_offset:x64 aux_size=aux_event->aux_size:x64"
- Enable trace events:
# cd /sys/kernel/debug/tracing # echo 1 > events/probe/enable # echo 1 > events/probe_perf/enable
- Executed the testing script and perf report command:
# sh test_cs_etm_snapshot.sh [ perf record: Woken up 7 times to write data ] [ perf record: Captured and wrote 19.534 MB /tmp/__perf_test.perf.data.miRDs ] # perf report -i /tmp/__perf_test.perf.data.miRDs
- At the end, I can get the tracing result:
# cd /sys/kernel/debug/tracing # cat trace
# entries-in-buffer/entries-written: 21/21 #P:6 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | dd-2206 [001] d.h3 1395.922396: perf_event_aux_event: (perf_event_aux_event+0x0/0x108) head=0x400000 size=0x400000 perf-2204 [002] .... 1395.922565: __auxtrace_mmap__read_L58: (0xaaaaab154394) idx=1 head=0x400000 offset=0x0 size=0x400000 dd-2206 [001] d.h3 1395.942658: perf_event_aux_event: (perf_event_aux_event+0x0/0x108) head=0x50b3f0 size=0x10b3f0 perf-2204 [002] .... 1395.942739: __auxtrace_mmap__read_L58: (0xaaaaab154394) idx=1 head=0x50b3f0 offset=0x400000 size=0x10b3f0 dd-2206 [001] d.h3 1396.000040: perf_event_aux_event: (perf_event_aux_event+0x0/0x108) head=0x90b3f0 size=0x400000 perf-2204 [002] .... 1396.000150: __auxtrace_mmap__read_L58: (0xaaaaab154394) idx=1 head=0x90b3f0 offset=0x50b3f0 size=0x400000 dd-2206 [001] d.h3 1396.023098: perf_event_aux_event: (perf_event_aux_event+0x0/0x108) head=0xb87ae0 size=0x27c6f0 perf-2204 [002] .... 1396.023197: __auxtrace_mmap__read_L58: (0xaaaaab154394) idx=1 head=0xb87ae0 offset=0x90b3f0 size=0x27c6f0 dd-2206 [001] d.h3 1396.087722: perf_event_aux_event: (perf_event_aux_event+0x0/0x108) head=0xf87ae0 size=0x400000 perf-2204 [002] .... 1396.087838: __auxtrace_mmap__read_L58: (0xaaaaab154394) idx=1 head=0xf87ae0 offset=0xb87ae0 size=0x400000 dd-2206 [001] d.h3 1396.131696: perf_event_aux_event: (perf_event_aux_event+0x0/0x108) head=0x1387ae0 size=0x400000 perf-2204 [002] .... 1396.131808: __auxtrace_mmap__read_L58: (0xaaaaab154394) idx=1 head=0x1387ae0 offset=0xf87ae0 size=0x400000 perf-2217 [003] .... 1439.581363: cs_etm__queue_aux_fragment_L63: (0xaaaac9582ba8) aux_offset=0x0 aux_size=0x400000 perf-2217 [003] .... 1439.581467: cs_etm__queue_aux_fragment_L63: (0xaaaac9582ba8) aux_offset=0x400000 aux_size=0x10b3f0 perf-2217 [003] .... 1439.581510: cs_etm__queue_aux_fragment_L63: (0xaaaac9582ba8) aux_offset=0x50b3f0 aux_size=0x400000 perf-2217 [003] .... 1439.581553: cs_etm__queue_aux_fragment_L63: (0xaaaac9582ba8) aux_offset=0x90b3f0 aux_size=0x27c6f0 perf-2217 [003] .... 1439.581595: cs_etm__queue_aux_fragment_L63: (0xaaaac9582ba8) aux_offset=0xb87ae0 aux_size=0x400000 perf-2217 [003] .... 1439.581638: cs_etm__queue_aux_fragment_L63: (0xaaaac9582ba8) aux_offset=0xf87ae0 aux_size=0x400000
We can see the recording AUX trace data in perf_event_aux_event() can be decoded properly in events cs_etm__queue_aux_fragment_L63().
Thanks, Leo