> Possibly. But according to Squid's own doc, the primary problems
> in Squid performance are
>
> 1) Not enough memory
Can indeed be alleviated by sendfile()...
> 2) Too slow disks
With a filesystem that can't handle the extreme dir sizes
that Squid uses. ReiserFS or another advanced filesystem
will speed up this bottleneck by more than just a considerable
amount...
> which as far as I can see aren't helped by sendfile. They also
> say "CPU limitations are rarely encountered except in very large
> caches".
This situation is also better handled by tree-based filesystems
and better buffer/cache administration.
> But too slow disks and not enough memory are directly
> related problems. If the kernel has frequently used
> disk files in the buffer cache, it still needs to copy
> the data to the user space server, then copy it back
> out onto a socket. With sendfile(), it can directly
> send data from the buffer cache without any user space
> involvement. In addition, we no longer need user
> space buffers in the server, cutting down on useless
> "memory duplication", allowing for more buffer cache.
This is very very true and might be able to speed up
large servers quite a lot.
Rik.
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