[Ffmpeg-devel] swscaler integration

Dave Dodge dododge
Fri Mar 17 11:29:11 CET 2006

On Thu, Mar 16, 2006 at 11:34:19AM -0500, Rich Felker wrote:
> On Thu, Mar 16, 2006 at 12:58:14PM +0100, Erik Slagter wrote:
> > I never understood why no unix version has a ioctl to set the pipe
> > buffer size.
> I guess then the kernel implementation would be a lot more complex
> (not just using a single page) and there would have to be a mechanism
> to prevent unbounded memory usage by pipe buffers.

It's been tried in Linux:


The basic result was that on SMP systems they were able to improve
performance on some benchmarks up by over 350%.  However on non-SMP
increasing the pipe buffers degraded things by up to 30%.

This test was done several years ago on a 2.4.x kernel.  I seem to
recall Linus rewriting the pipe implementation in the last year or two
so the results might not apply any more.

                                                  -Dave Dodge

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