* Waiman Long <[email protected]> wrote:
> Enabling CONFIG_LOCKDEP and other related debug options will greatly
> reduce system performance. This patchset aims to reduce the performance
> slowdown caused by the lockdep code.
>
> Patch 1 just removes an inline function that wasn't used.
>
> Patches 2 and 3 are minor twists to optimize the code.
>
> Patch 4 makes class->ops a per-cpu counter.
>
> Patch 5 moves the lock_release() call outside of a lock critical section.
>
> Parallel kernel compilation tests (make -j <#cpu>) were performed on
> 2 different systems:
>
> 1) an 1-socket 22-core 44-thread Skylake system
> 2) a 4-socket 72-core 144-thread Broadwell system
>
> The build times with pre-patch and post-patch debug kernels were:
>
> System Pre-patch Post-patch %Change
> ------ --------- ---------- -------
> 1-socket 8m53.9s 8m41.2s -2.4%
> 4-socket 7m27.0s 5m31.0s -26%
>
> I think it is the last 2 patches that yield most of the performance
> improvement.
Impressive speedup!
Mind including the non-lockdep numbers as well, for reference?
Thanks,
Ingo
