Messages in this thread | | | Date | Mon, 24 Jul 2023 11:50:06 +0800 | From | Changbin Du <> | Subject | Re: [PATCH] perf: add new option '--workload-attr' to set workload sched_policy/priority/mask |
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On Wed, Jul 19, 2023 at 09:55:39AM -0700, Ian Rogers wrote: > On Fri, Jul 14, 2023 at 12:19 AM Changbin Du <changbin.du@huawei.com> wrote: > > > > On Fri, Jul 14, 2023 at 10:06:31AM +0300, Adrian Hunter wrote: > > > On 13/07/23 11:58, Changbin Du wrote: > > > > To get consistent benchmarking results, sometimes we need to set the > > > > sched_policy/priority/mask of the workload to reduce system noise. > > > > > > > > For example, CPU binding is required on big.little system. > > > > > > > > $ perf stat -r 10 -- taskset -c 0 ls > > > > > > > > Nevertheless, the 'taskset' is also counted here. > > > > > > > > To get away of the middleman, this adds a new option '--workload-attr' to > > > > do the same jobs for stat and record commands. > > > > > > > > $ sudo perf stat --workload-attr fifo,40,0x1 -- ls > > > > > > > > Above will make 'ls' run on CPU #0 with fifo scheduler and realtime > > > > priority is 40. > > > > > > Aren't there ways to set up a process then start perf using -p <pid> > > > then let the process continue. > > > > > By that you need a mechanism to pause the new spawnned process and wait perf to > > attach. Or setup the sched properties by the app itself. But sometimes we just > > simply want to run the app through and measure some events. With > > --workload-attr, we do not need extra setup works. > > To my naive eyes this looks to be a broadly useful addition. Some thoughts: > - "cpu-mask" as the command line argument name, this is "-C" and > "--cpu" elsewhere, so perhaps just "cpu" as the mask is perhaps > confusing. I changed the name of third field to cpu-list, and use perf_cpu_map_new() to parse the list. This api doesn't accept a mask.
--workload-attr <sched_policy[,priority][,cpu-list]> setup target workload (the <command>) attributes:
sched_policy: other|fifo|rr|batch|idle priority: scheduling priority for fifo|rr, nice value for other cpu-list: CPU affinity. e.g. 1-2:4 is processors #1, #2, and #4
> - could we get a test? Perhaps add a case to tools/perf/tests/shell/stat.sh: > https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/tests/shell/stat.sh?h=perf-tools-next > No problem, I will add a testcase there.
> Thanks, > Ian > > > -- > > Cheers, > > Changbin Du
-- Cheers, Changbin Du
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