Messages in this thread | | | Date | Mon, 28 Feb 2005 12:36:56 +0100 | From | Christian Schmid <> | Subject | Re: Slowdown on high-load machines with 3000 sockets |
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Nick Piggin wrote: > 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.
Acutally, thats why I changed it to manual readahead. I thought the slowdown comes from some weird read-ahead settings. But with the manual read-ahead, this problem appears as well. Its still a phenomenon why this slowdown definetly disappears when I raise /proc/sys/vm/min_free_kbytes to 1024000 (until it hits around 4500 sockets) but it seems not to work with smaller or bigger values....
> Also, can we get a testcase (ie. minimal compilable code) to reproduce > this problem?
This is a complex code, thats why I really want to avoid this..... Feel free to ask for traces or anything you want to know though.
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