On 2/2/25 00:18, Suren Baghdasaryan wrote: > When a sizable code section is protected by a disabled static key, that > code gets into the instruction cache even though it's not executed and > consumes the cache, increasing cache misses. This can be remedied by > moving such code into a separate uninlined function. > On a Pixel6 phone, slab allocation profiling overhead measured with > CONFIG_MEM_ALLOC_PROFILING=y and profiling disabled is: > > baseline modified > Big core 3.31% 0.17% > Medium core 3.79% 0.57% > Little core 6.68% 1.28% > > This improvement comes at the expense of the configuration when profiling > gets enabled, since there is now an additional function call. The overhead > from this additional call on Pixel6 is: > > Big core 0.66% > Middle core 1.23% > Little core 2.42% > > However this is negligible when compared with the overall overhead of the > memory allocation profiling when it is enabled. > On x86 this patch does not make noticeable difference because the overhead > with mem_alloc_profiling_key disabled is much lower (under 1%) to start > with, so any improvement is less visible and hard to distinguish from the > noise. The overhead from additional call when profiling is enabled is also > within noise levels. > > Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
