Messages in this thread | | | Date | Tue, 15 Oct 2013 09:30:41 -0600 | From | David Ahern <> | Subject | Re: [PATCH 3/3] perf record: mmap output file |
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On 10/15/13 9:27 AM, Ingo Molnar wrote: > > * Peter Zijlstra <peterz@infradead.org> wrote: > >> On Tue, Oct 15, 2013 at 11:32:45AM -0300, Arnaldo Carvalho de Melo wrote: >> >>> Jiri and PeterZ probaby will have comments here... ;-) :-) >> >> The only complication with splice is the vmalloc support; other than >> that it should be fairly straight fwd. > > In the initial version we could skip splice support for vmalloc > ring-buffer, to keep things simple. > > Wanna send a patch for people to try? Looks like there's real interest in > speeding up perf record as much as possible!
My second -- and more important -- concern about splice has been dropped from this path:
"splice is also a system call and it would have to be invoked for each mmap each trip through the loop -- just like write() does today -- so it does not solve the feedback loop problem. "
Am I missing something on how splice works?
David
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