Messages in this thread |  | | Subject | Re: Really slow netstat and /proc/net/tcp in 2.4 | From | Andi Kleen <> | Date | 12 Oct 2001 21:56:01 +0200 |
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In article <20011011125538.C10868@netnation.com>, Simon Kirby <sim@netnation.com> writes: > On Thu, Oct 11, 2001 at 11:30:25PM +0400, kuznet@ms2.inr.ac.ru wrote: >> Hello! >> >> > Is there something that changed from 2.2 -> 2.4 with regards to the >> > speed of netstat and /proc/net/tcp? >> >> Incredibly high size of hash table, I think. >> At least here size is ~1MB. And all this is read each 1K of data read >> via /proc/ :-)
> So it's walking the hash table per block read, and the hash table is very > large? Hmm. I notice it's a bit faster if I use dd if=/proc/net/tcp > of=/dev/null bs=1024k, but not much.
> Is it possible to fix this? Was the 2.2 hash table just that much > smaller?
The hash table is likely to big anyways; eating cache and not helping that much. If you're interested in some testing I can send you patches to change it by hand and collect statistics for average hash queue length. Then you can figure out a good size for your workload with some work. Longer time I think the table sizing heuristics are far too aggressive and need to be throttled back; but that needs more data from real servers.
-Andi
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