Re: [RFC PATCH v4 00/11] powerpc: switch VDSO to C implementation.
From: Segher Boessenkool <hidden>
Date: 2020-01-17 09:00:01
Also in:
linux-mips, linuxppc-dev, lkml
Hi! On Thu, Jan 16, 2020 at 05:58:24PM +0000, Christophe Leroy wrote:
On a powerpc8xx, with current powerpc/32 ASM VDSO: gettimeofday: vdso: 907 nsec/call clock-getres-realtime: vdso: 484 nsec/call clock-gettime-realtime: vdso: 899 nsec/call The first patch adds VDSO generic C support without any changes to common code. Performance is as follows: gettimeofday: vdso: 1211 nsec/call clock-getres-realtime: vdso: 722 nsec/call clock-gettime-realtime: vdso: 1216 nsec/call Then a few changes in the common code have allowed performance improvement. At the end of the series we have: gettimeofday: vdso: 974 nsec/call clock-getres-realtime: vdso: 545 nsec/call clock-gettime-realtime: vdso: 941 nsec/call The final result is rather close to pure ASM VDSO: * 7% more on gettimeofday (9 cycles) * 5% more on clock-gettime-realtime (6 cycles) * 12% more on clock-getres-realtime (8 cycles)
Nice! Much better. It should be tested on more representative hardware, too, but this looks promising alright :-) Segher _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel