[ Upstream commit 95035c5e16 ]
'perf record' will error out if both --delay and LBR are applied.
For example:
# perf record -D 1000 -a -e cycles -j any -- sleep 2
Error:
dummy:HG: PMU Hardware doesn't support sampling/overflow-interrupts.
Try 'perf stat'
#
A dummy event is added implicitly for initial delay, which has the same
configurations as real sampling events. The dummy event is a software
event. If LBR is configured, perf must error out.
The dummy event will only be used to track PERF_RECORD_MMAP while perf
waits for the initial delay to enable the real events. The BRANCH_STACK
bit can be safely cleared for the dummy event.
After applying the patch:
# perf record -D 1000 -a -e cycles -j any -- sleep 2
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 1.054 MB perf.data (828 samples) ]
#
Reported-by: Sunil K Pandey <sunil.k.pandey@intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1531145722-16404-1-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
968f03158d