Re: Unexpected splice "always copy" behavior observed

From: Linus Torvalds
Date: Wed May 19 2010 - 11:03:23 EST




On Wed, 19 May 2010, Steven Rostedt wrote:

> On Wed, 2010-05-19 at 07:39 -0700, Linus Torvalds wrote:
>
> > The real limitation is likely always going to be the fact that it has to
> > be page-aligned and a full page. For a lot of splice inputs, that simply
> > won't be the case, and you'll end up copying for alignment reasons anyway.
>
> That's understandable. For the use cases of splice I use, I work to make
> it page aligned and full pages. Anyone else using splice for
> optimizations, should do the same. It only makes sense.
>
> The end of buffer may not be a full page, but then it's the end anyway,
> and I'm not as interested in the speed.

Btw, since you apparently have a real case - is the "splice to file"
always just an append? IOW, if I'm not right in assuming that the only
sane thing people would reasonable care about is "append to a file", then
holler now.

Linus
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