Re: [PATCH] zerocopy NFS updated

Hirokazu Takahashi
2002-04-20T10:15:25Z

Hi,

> With all this talk on serialization on UDP, and have a question. first, let
> me explain the situation. I have an NFS test which calls 48 clients to read
> the same 200 MB file on the same server. I record the time for all the
> clients to finish and then calculate the total throughput. The server is a
> 4-way IA32. (I used this test to measure the zerocopy/tcp/nfs patch) Now,
> right before the test, the 200 MB file is created on the server, so there is
> no disk IO at all during the test. It's just an very simple cached read.
> Now, when the clients use udp, I can only get a run queue length of 1, and I
> have confirmed there is only one nfsd thread in svc_process() at one time,
> and I am 65% idle. With tcp, I can get all nfsd threads running, and max all
> CPUs. Am I experiencing a bottleneck/serialization due to a single UDP
> socket?

What version do you use?
2.5.8 kernel has a problem in readahead of NFSD.
It doesn't work at all.

It can be easy to fix.

Thank you,
Hirokazu Takahashi.