Re: Is sendfile all that sexy?

Ingo Molnar (mingo@elte.hu)
Sun, 14 Jan 2001 20:09:54 +0100 (CET)


On Sun, 14 Jan 2001, jamal wrote:

> Already doing the single file, single process. [...]

in this case there could still be valid performance differences, as
copying from user-space is cheaper than copying from the pagecache. To
rule out SMP interactions, you could try a UP-IOAPIC kernel on that box.

(I'm also curious what kind of numbers you'll get with the zerocopy
patch.)

> However, i do run by time which means i could read the file from the
> begining(offset 0) to the end then re-do it for as many times as
> 15secs would allow. Does this affect it? [...]

no, in the case of a single thread this should have minimum impact. But
i'd suggest to increase the /proc/sys/net/tcp*mem* values (to 1MB or
more).

Ingo

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