Re: Slowdown on high-load machines with 3000 sockets

Nick Piggin
2005-02-28T05:13:57Z

Christian Schmid wrote:
> I already tried with 300 KB and even used a perl-hash as a horrible-slow
> buffer for a readahead-replacement. It still slowed down on the syswrite
> to the socket. Thats the strange thing.
>

Do you have to use manual readahead though? What is the performance
like if you just let the kernel do its own thing? The kernel's
readahead provides things like automatic scaling and thrashing
control, so if possible you should just stick to that.

Although you may want to experiment with the maximum readahead on your
working disks:
/sys/block/???/queue/read_ahead_kb

Also, can we get a testcase (ie. minimal compilable code) to reproduce
this problem?

Thanks,
Nick