lkml.org 
[lkml]   [2001]   [Oct]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: Really slow netstat and /proc/net/tcp in 2.4
From
Date
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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:08    [W:0.061 / U:4.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site