On Mon, Feb 3, 2025 at 4:47 PM Shakeel Butt <shakeel.butt@xxxxxxxxx> wrote: > > On Sat, Feb 01, 2025 at 03:18:02PM -0800, 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, page allocation profiling overhead measured with > > CONFIG_MEM_ALLOC_PROFILING=y and profiling disabled is: > > > > baseline modified > > Big core 4.93% 1.53% > > Medium core 4.39% 1.41% > > Little core 1.02% 0.36% > > > > 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 0.24% > > Middle core 0.63% > > Little core 1.1% > > > > 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> > > Reviewed-by: Shakeel Butt <shakeel.butt@xxxxxxxxx> > > One question: Is there any plan to enable MEM_ALLOC_PROFILING by default > in future? It's left up to each distribution. In Android Common Kernel we are enabling it with CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT=n and allow vendors to enable it using kernel command line parameters. >
