Subject: Re: why nfs server delay 10ms in nfsd_write()?
From: Avi Kivity <avi@argo.co.il>
To: Lee Revell <rlrevell@joe-job.com>
Cc: Peter Staubach <staubach@redhat.com>, steve <lingxiang@huawei.com>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
       "zhangtiger@huawei.com" <zhangtiger@huawei.com>
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Date: Thu, 19 May 2005 17:13:29 +0300
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On Thu, 2005-05-19 at 09:59 -0400, Lee Revell wrote:
> On Thu, 2005-05-19 at 08:53 -0400, Peter Staubach wrote:
> > There are certainly many others way to get gathering, without adding an
> > artificial delay.  There are already delay slots built into the code 
> > which could
> > be used to trigger the gathering, so with a little bit different 
> > architecture, the
> > performance increases could be achieved.
> > 
> > Some implementations actually do write gathering with NFSv3, even.  Is
> > this interesting enough to play with?  I suspect that just doing the 
> > work for
> > NFSv2 is not...
> 
> Also, how do you explain the big performance hit that steve observed?
> Write gathering is supposed to help performance, but it's a big loss on
> his test...
> 

that would depend on the NFS client and the application. for example, if
the NFS client has no (or low) concurrency, then write gathering would
reduce preformance.


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