Re: [PATCH] perf jevents: make events order more deterministic

[Nazar Kazakov <nazar.kazakov@codethink.co.uk>]

On 2026-07-06 19:04, Ian Rogers wrote:
> On Mon, Jul 6, 2026 at 10:57 AM Nazar Kazakov
> <nazar.kazakov@codethink.co.uk> wrote:
>> 
>> Some of the events have the same name, but differing descriptions. 
>> This
>> leads to a non-deterministic sorting order, so fix by adding the
>> description field to the order.
>> 
>> Signed-off-by: Nazar Kazakov <nazar.kazakov@codethink.co.uk>
> 
> This shouldn't be an issue; can you give an example? I mean, with:
> $ perf stat -e event1,event1 true
> There's only one meaning for what event1 is. There is wildcard
> support, but that's not the same as having the same event more than
> once, differing only by description. Note, I deliberately use events
> with perf stat in the example because the metrics build on the regular
> event parsing code.

I meant sorting order during build time: 
tools/perf/pmu-events/pmu-events.c
changes between different builds, you can see an example of diffoscope
output here 
https://freedesktop-sdk.gitlab.io/-/freedesktop-sdk/-/jobs/15174060131/artifacts/result_folder/components/perf.bst/index.html

/* offset=5995059 */ 
"lpm_l2_rfo_misses\000lpm_l2;lpm_l2_rfo\000d_ratio(L2_RQSTS.RFO_MISS, 
duration_time)\000\000L2 cache request for ownership (RFO) misses per 
second\000\0001misses/s\000\000\000\000000"
/* offset=5995210 */ 
"lpm_l2_rfo_misses\000lpm_l2;lpm_l2_rfo\000d_ratio(L2_RQSTS.RFO_MISS, 
L2_RQSTS.RFO_HIT + L2_RQSTS.RFO_MISS)\000\000L2 cache request for 
ownership (RFO) misses\000\000100%\000\000\000\000000"

vs

/* offset=5995059 */ 
"lpm_l2_rfo_misses\000lpm_l2;lpm_l2_rfo\000d_ratio(L2_RQSTS.RFO_MISS, 
L2_RQSTS.RFO_HIT + L2_RQSTS.RFO_MISS)\000\000L2 cache request for 
ownership (RFO) misses\000\000100%\000\000\000\000000"
/* offset=5995217 */ 
"lpm_l2_rfo_misses\000lpm_l2;lpm_l2_rfo\000d_ratio(L2_RQSTS.RFO_MISS, 
duration_time)\000\000L2 cache request for ownership (RFO) misses per 
second\000\0001misses/s\000\000\000\000000"

That leads to non-reproducible binaries, even though the functionality
is probably the same.

Thanks,
Nazar Kazakov