Messages in this thread | | | Date | Mon, 19 Jun 2017 16:24:01 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH v3 1/n] perf/core: addressing 4x slowdown during per-process profiling of STREAM benchmark on Intel Xeon Phi |
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On Mon, Jun 19, 2017 at 08:21:51AM -0700, Andi Kleen wrote: > > I was trying to get a feel for how that compares to what we can do > > today. For other reasons (e.g. fd exhaustion), opening NR_CPUS * n > > You just have to increase the fd limit. The 1024 fd default is just > archaic for larger systems and doesn't really make any sense because > it only controls very small amounts of kernel memory. > > > events might not be a great idea on systems with a huge number of CPUs. > > We might want a heuristic in the perf tool regardless. > > But there's no alternative: we have to measure all CPUs with all events.
You can measure the process on all CPUs by using 1 event without a CPU filter, rather than NR_CPUS events.
Thanks, Mark.
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