Hi Ilpo, On 3/27/26 10:49 AM, Ilpo Järvinen wrote: > On Fri, 13 Mar 2026, Reinette Chatre wrote: > >> The L3 CAT test loads a buffer into cache that is proportional to the L3 >> size allocated for the workload and measures cache misses when accessing >> the buffer as a test of L3 occupancy. When loading the buffer it can be >> assumed that a portion of the buffer will be loaded into the L2 cache and >> depending on cache design may not be present in L3. It is thus possible >> for data to not be in L3 but also not trigger an L3 cache miss when >> accessed. >> >> Reduce impact of L2 on the L3 CAT test by, if L2 allocation is supported, >> minimizing the portion of L2 that the workload can allocate into. This >> encourages most of buffer to be loaded into L3 and support better >> comparison between buffer size, cache portion, and cache misses when >> accessing the buffer. >> >> Signed-off-by: Reinette Chatre <[email protected]> >> Tested-by: Chen Yu <[email protected]> >> --- >> Changes since v2: >> - Add Chen Yu's tag. >> --- >> tools/testing/selftests/resctrl/cat_test.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/tools/testing/selftests/resctrl/cat_test.c >> b/tools/testing/selftests/resctrl/cat_test.c >> index 6aac03147d41..371a2f26dc47 100644 >> --- a/tools/testing/selftests/resctrl/cat_test.c >> +++ b/tools/testing/selftests/resctrl/cat_test.c >> @@ -157,6 +157,10 @@ static int cat_test(const struct resctrl_test *test, >> if (ret) >> goto reset_affinity; >> >> + ret = minimize_l2_occupancy(test, uparams, param); >> + if (ret) >> + goto reset_affinity; >> + >> perf_event_attr_initialize(&pea, PERF_COUNT_HW_CACHE_MISSES); >> pe_fd = perf_open(&pea, bm_pid, uparams->cpu); >> if (pe_fd < 0) { >> > > Reviewed-by: Ilpo Järvinen <[email protected]> >
Thank you very much for this and all the other reviews. Much appreciated. Reinette
