Re: pipe testing and kernel copyin/copyout/bcopy performance

[Hiten Pandya <hmp@xxxxxxxxxxxxx>]

Matthew Dillon wrote:

>     Just to let people know, in case anyone is wondering why I have been so
>     quiet lately :-)
>
>     I've been running some major pipe benchmarks to compare various pipe 
>     optimizations as part of a paper (FreeBSD's) Alan Cox and I are writing.
>
>     At the same time I've delved deeply into the AMD64 and have been working
>     on optimizing the kernel bcopy, memcpy, copyin, and copyout to use
>     XMM instructions when possible.

	Didn't you mention to me something about FPU context switch
	overhead?  Secondly, wouldn't the XMM based copyin, bcopy etc
	make small transfers slow?

		-Hiten
		hmp@xxxxxxxxxxxxx