Re: Massive slowdown when re-querying large nfs dir

From: Al Boldi
Date: Tue Nov 06 2007 - 06:28:29 EST


Al Boldi wrote:
> There is a massive (3-18x) slowdown when re-querying a large nfs dir (2k+
> entries) using a simple ls -l.
>
> On 2.6.23 client and server running userland rpc.nfs.V2:
> first try: time -p ls -l <2k+ entry dir> in ~2.5sec
> more tries: time -p ls -l <2k+ entry dir> in ~8sec
>
> first try: time -p ls -l <5k+ entry dir> in ~9sec
> more tries: time -p ls -l <5k+ entry dir> in ~180sec
>
> On 2.6.23 client and 2.4.31 server running userland rpc.nfs.V2:
> first try: time -p ls -l <2k+ entry dir> in ~2.5sec
> more tries: time -p ls -l <2k+ entry dir> in ~7sec
>
> first try: time -p ls -l <5k+ entry dir> in ~8sec
> more tries: time -p ls -l <5k+ entry dir> in ~43sec
>
> Remounting the nfs-dir on the client resets the problem.
>
> Any ideas?

Ok, I played some more with this, and it turns out that nfsV3 is a lot
faster. But, this does not explain why the 2.4.31 kernel is still over
4-times faster than 2.6.23.

Can anybody explain what's going on?


Thanks!

--
Al

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