Re: [PATCH v5 00/22] powerpc/32: Implement C syscall entry/exit

Nicholas Piggin
2021-02-09T01:04:22Z

Excerpts from Christophe Leroy's message of February 9, 2021 1:10 am:
> This series implements C syscall entry/exit for PPC32. It reuses
> the work already done for PPC64.
>
> This series is based on today's merge-test (b6f72fc05389e3fc694bf5a5fa1bbd33f61879e0)
>
> In terms on performance we have the following number of cycles on an
> 8xx running null_syscall benchmark:
> - mainline: 296 cycles
> - after patch 4: 283 cycles
> - after patch 16: 304 cycles
> - after patch 17: 348 cycles
> - at the end of the series: 320 cycles
>
> So in summary, we have a degradation of performance of 8% on null_syscall.
>
> I think it is not a big degradation, it is worth it.

I guess it's 13% from 283. But it's very nice to use the shared C code.

There might be a few more percent speedup in there we can find later.

Thanks,
Nick