Re: [PATCH] perf bench: Add benchmark of find_next_bit

2020-07-29 Thread Ian Rogers
On Wed, Jul 29, 2020 at 1:44 PM Arnaldo Carvalho de Melo wrote: > > Em Wed, Jul 29, 2020 at 04:59:18PM -0300, Arnaldo Carvalho de Melo escreveu: > > Em Tue, Jul 28, 2020 at 08:51:52AM -0300, Arnaldo Carvalho de Melo escreveu: > > > Em Fri, Jul 24, 2020 at 12:19:59AM -0700, Ian Rogers escreveu: >

Re: [PATCH] perf bench: Add benchmark of find_next_bit

2020-07-29 Thread Arnaldo Carvalho de Melo
Em Wed, Jul 29, 2020 at 04:59:18PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Tue, Jul 28, 2020 at 08:51:52AM -0300, Arnaldo Carvalho de Melo escreveu: > > Em Fri, Jul 24, 2020 at 12:19:59AM -0700, Ian Rogers escreveu: > > > for_each_set_bit, or similar functions like for_each_cpu, may be hot

Re: [PATCH] perf bench: Add benchmark of find_next_bit

2020-07-29 Thread Arnaldo Carvalho de Melo
Em Tue, Jul 28, 2020 at 08:51:52AM -0300, Arnaldo Carvalho de Melo escreveu: > Em Fri, Jul 24, 2020 at 12:19:59AM -0700, Ian Rogers escreveu: > > for_each_set_bit, or similar functions like for_each_cpu, may be hot > > within the kernel. If many bits were set then one could imagine on > > Intel a

Re: [PATCH] perf bench: Add benchmark of find_next_bit

2020-07-28 Thread Arnaldo Carvalho de Melo
Em Fri, Jul 24, 2020 at 12:19:59AM -0700, Ian Rogers escreveu: > for_each_set_bit, or similar functions like for_each_cpu, may be hot > within the kernel. If many bits were set then one could imagine on > Intel a "bt" instruction with every bit may be faster than the function > call and word

Re: [PATCH] perf bench: Add benchmark of find_next_bit

2020-07-24 Thread Ian Rogers
On Fri, Jul 24, 2020 at 7:45 AM Andi Kleen wrote: > > On Fri, Jul 24, 2020 at 12:19:59AM -0700, Ian Rogers wrote: > > for_each_set_bit, or similar functions like for_each_cpu, may be hot > > within the kernel. If many bits were set then one could imagine on > > Intel a "bt" instruction with every

Re: [PATCH] perf bench: Add benchmark of find_next_bit

2020-07-24 Thread Andi Kleen
On Fri, Jul 24, 2020 at 12:19:59AM -0700, Ian Rogers wrote: > for_each_set_bit, or similar functions like for_each_cpu, may be hot > within the kernel. If many bits were set then one could imagine on > Intel a "bt" instruction with every bit may be faster than the function > call and word length

[PATCH] perf bench: Add benchmark of find_next_bit

2020-07-24 Thread Ian Rogers
for_each_set_bit, or similar functions like for_each_cpu, may be hot within the kernel. If many bits were set then one could imagine on Intel a "bt" instruction with every bit may be faster than the function call and word length find_next_bit logic. Add a benchmark to measure this. This benchmark