Re: [PATCH v1 2/2] perf record: Support weak groups

[Jiri Olsa <jolsa@redhat.com>]

On Mon, Oct 01, 2018 at 12:59:27PM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
> 
> Implement a weak group fallback for perf record, similar to the existing perf stat support.
> This allows to use groups that might be longer than the available counters without
> failing.
> 
> Before:
> 
> $ perf record  -e '{cycles,cache-misses,cache-references,cpu_clk_unhalted.thread,cycles,cycles,cycles}' -a sleep 1
> Error:
> The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cycles).
> /bin/dmesg | grep -i perf may provide additional information.
> 
> After:
> 
> $ ./perf record  -e '{cycles,cache-misses,cache-references,cpu_clk_unhalted.thread,cycles,cycles,cycles}:W' -a sleep 1
> WARNING: No sample_id_all support, falling back to unordered processing
> [ perf record: Woken up 3 times to write data ]
> [ perf record: Captured and wrote 8.136 MB perf.data (134069 samples) ]
> 
> Signed-off-by: Andi Kleen <ak@linux.intel.com>

Acked-by: Jiri Olsa <jolsa@kernel.org>

thanks,
jirka