2.2 -> 2.4: /proc/net/tcp 10x slower ?

2.2 -> 2.4: /proc/net/tcp 10x slower ?

[Sven Rudolph]

Usually identd's on Linux parse /proc/net/tcp.

When migrating from Linux 2.2.17 to 2.4.2 identd became much slower.

I traced it back to the point where /proc/net/tcp is read.

On the same slightly loaded system:

2.2.17 $ time cat /proc/net/tcp >/dev/null
real    0m0.004s
user    0m0.000s
sys     0m0.010s

(Or sometimes 0.000s due to granularity)

2.2.17 $ time cat /proc/net/tcp >/dev/null
real    0m0.083s
user    0m0.000s
sys     0m0.080s


Is this expected? Or is there a more efficient interface that identd
should use?

	Sven

Re: 2.2 -> 2.4: /proc/net/tcp 10x slower ?

[Sean Hunter]

The identd wot I wrote is still fast as anything on 2.4 :)

As you can see from this teeny sample of my ident log, I take just a little
over 1/100th of a second to respond (on average). :)

2001-02-25 16:18:35.714731500 Q [194.75.152.225] - [32907, 25]
2001-02-25 16:18:35.726085500 A [194.75.152.225] - [9a0c62e79c0df893bb96dd74/3a99305b/b0164] for [32907, 25] UID [506]
2001-02-26 09:41:02.535514500 Q [195.92.249.252] - [33363, 21]
2001-02-26 09:41:02.548884500 A [195.92.249.252] - [8c0babd7b8ab6830b7092839/3a9a24ae/8454c] for [33363, 21] UID [500]

By the way, the intention of my ident server was not to be fast, but just to be
a little simpler and less over-engineered than pidentd, and not to give out any
site-specific information (uid's etc).  The speed was a bonus.

Sean


On Mon, Feb 26, 2001 at 03:12:01PM +0100, Sven Rudolph wrote:
> Usually identd's on Linux parse /proc/net/tcp.
> 
> When migrating from Linux 2.2.17 to 2.4.2 identd became much slower.
> 
> I traced it back to the point where /proc/net/tcp is read.
> 
> On the same slightly loaded system:
> 
> 2.2.17 $ time cat /proc/net/tcp >/dev/null
> real    0m0.004s
> user    0m0.000s
> sys     0m0.010s
> 
> (Or sometimes 0.000s due to granularity)
> 
> 2.2.17 $ time cat /proc/net/tcp >/dev/null
> real    0m0.083s
> user    0m0.000s
> sys     0m0.080s
> 
> 
> Is this expected? Or is there a more efficient interface that identd
> should use?
> 
> 	Sven
> 
> -
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