Messages in this thread | | | Subject | Re: why nfs server delay 10ms in nfsd_write()? | From | Trond Myklebust <> | Date | Wed, 18 May 2005 23:08:48 -0400 |
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to den 19.05.2005 Klokka 10:46 (+0800) skreiv steve:
> i have 2 questions: > 1.i don't know why do we have to sleep for 10 ms, why not do sync immediately? > 2.what will happen if we don't sleep for 10ms? > when i delete these codes, i get a good result, and the write performace improved from 300KB/s to 18MB/s
See http://www.usenix.org/publications/library/proceedings/sf94/full_papers/juszczak.a
Write gathering is basically a method for improving NFSv2 writes without any protocol changes. Later, NFSv3 introduced the more efficient concept of "unstable" writes into the protocol (see http://www.netapp.com/ftp/NFSv3_Rev_3.pdf).
You can turn NFSv2 write gathering on and off using the wdelay/no_wdelay export options ('man 5 exports')
Trond
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