Messages in this thread | | | Subject | Re: Awful NFS performance with attached test program | From | Trond Myklebust <> | Date | Mon, 19 Jan 2004 16:53:46 -0500 |
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På må , 19/01/2004 klokka 16:16, skreiv jlnance@unity.ncsu.edu: > Hello All, > The attached program demonstrates a problem I am having writing to > files on an NFS file system. It works by creating a file, and then > seeking through the file to update it. The problem I am seeing is that > the seek/update stage takes more than 10X as long as the amount of time > required to initially create the file. And its not even seeking in > some strange pattern. > > I am running this with a 2.4.20 (red hat patched) kernel. I have not > tried it with 2.6. I have played with various mount options, but they > do not seem to make much difference. Here is one example that I used:
So you are surprised that writing the same dataset by putting one integer onto each kernel page takes much more time than placing the entire dataset onto just a few kernel pages? 'cos I'm not...
Have a look at the nfsstat output and you'll see what I mean. Doing the former will necessarily end up generating *a lot* more NFS write requests.
Cheers, Trond - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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