Re: [PATCH 3/3] perf record: mmap output file

[Arnaldo Carvalho de Melo]

Em Tue, Oct 15, 2013 at 08:04:15AM -0600, David Ahern escreveu:
> On 10/8/13 11:59 PM, Ingo Molnar wrote:
> > 2)

> > Yet another method would be to avoid the copies altogether via the splice
> > system-call - see:

> >	git grep splice kernel/trace/

> > To make splice low-overhead we'd have to introduce a mode to not mmap
> > the data part of the perf ring-buffer and splice the data straight
> > from the perf fd into a temporary pipe and over from the pipe into
> > the target file (or socket).

> I looked into splice and it was not clear it would be a good match.
> First, perf is setup to pull data from mmap's and there is not a 1:1
> association between mmap's and fd's (fd_in for splice). Second and

Jiri and PeterZ probaby will have comments here... ;-) :-)

Jiri even have patches, IIRC.

- Arnaldo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/