[lkml]   [2006]   [Nov]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: splice/vmsplice performance test results
On Thu, Nov 16 2006, David Miller wrote:
> From: "Jim Schutt" <>
> Date: Thu, 16 Nov 2006 11:08:59 -0700
> > Or is read+write really the fastest way to get data off a
> > socket and into a file?
> There is still no explicit TCP support for splice/vmsplice so things
> get copied around and most of the other advantaves of splice/vmplice
> aren't obtained either. So perhaps that explains your numbers.

There should not be any copying for tcp send, at least no more than what
sendfile() did/does. Hmm?

> Jens Axboe tries to get things working, and others have looked into it
> too, but adding TCP support is hard and for several reasons folks like
> Alexey Kuznetsov and Evgeniy Polyakov believe that sys_receivefile()
> is an interface much better suited for TCP receive.
> splice/vmsplice has a lot of state connected to a transaction, and
> perhaps that is part of why Evgeniy and Alexey have trouble wrapping
> their brains around an efficient implementation.

I hope to try and see if I can help get some of that done, however I
need all the help I can get on the networking side. Not sure I
understand why it has to be so difficult, if we need to define a wrapper
container instead of passing down a pipe that is completely fine with
me. The networking code basically just needs to hang on to the
pipe_buffer and release it on ack for send, receive is somewhat more
involved (and I don't know enough about networking to voice any
half-intelligent opinion on that!).

I would just consider it a damn shame if we cannot complete the splice
family and need to punt to something else for net receive.

Jens Axboe

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2006-11-16 22:25    [W:0.067 / U:0.080 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site