Re: why nfs server delay 10ms in nfsd_write()?

[Peter Staubach]

steve wrote:

> Hi Peter,
> My envionment looks like that:
>
> NFS ServerïSuse9 Enterprise 
> NFS ClientïRedhat AS3.0(kernel 2.4.21) 
>
> I made a ramdisk and export it with nfs
> Server and Client are connected with 1000Mbps
>
> mount the ramdisk on the client with parameters: -t nfs -o rw,noac
>
> then test with iometer and the parameters are: 
> Outstanding IO is 32, transfer request size is 512, sequential write
> the result is about 300KB/s, iops is about 600
>
> with dd test i find the delay most cost at the server.
>
> i agree with Avi that "if the NFS client has no (or low) concurrency, then write gathering would reduce preformance"

I would agree too with Avi, and especially in this configuration...

I think that we could construct a writer gathering implementation which 
did not
show measurable performance impact in this sort of situation though still.

Thanx...

ps
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