On 3/18/06, Wu Fengguang <[email protected]> wrote:
> On Sat, Mar 18, 2006 at 10:10:43PM -0500, Jon Smirl wrote:
> > This is probably a readahead problem. The lighttpd people that are
> > encountering this problem are not regular lkml readers.
> >
> > http://bugzilla.kernel.org/show_bug.cgi?id=5949
>
> [QUOTE]
> My general conclusion is that since they were able to write a user
> space implementation that avoids the problem something must be broken
> in the kernel readahead logic for sendfile().
>
> Maybe the user space solution does the trick by using a larger window size?
>
> IMHO, the stock read-ahead is not designed with extremely high concurrency in
> mind. However, 100 streams should not be a problem at all.
Has anyone checked to see if the readahead logic is working as
expected from sendfile? IO from sendfile is a different type of
context than IO from user space, there could be sendfile specific
problems. If window size is the trick, shouldn't sendfile
automatically adapt it's window size? I don't think you can control
the sendfile window size from user space.
The goal of sendfile is to be the most optimal way to send a file over
the network. This is a case where user space code is easily beating
it.
--
Jon Smirl
[email protected]
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
