Re: [LKP] [SUNRPC] 0472e47660: fsmark.app_overhead 16.0% regression

From: Xing Zhengjun
Date: Mon Jul 08 2019 - 22:39:24 EST


Hi Trond,

On 7/8/2019 7:44 PM, Trond Myklebust wrote:
I've asked several times now about how to interpret your results. As far as I can tell from your numbers, the overhead appears to be entirely contained in the NUMA section of your results.
IOW: it would appear to be a scheduling overhead due to NUMA. I've been asking whether or not that is a correct interpretation of the numbers you published.
Thanks for your feedback. I used the same hardware and the same test parameters to test the two commits:
e791f8e938 ("SUNRPC: Convert xs_send_kvec() to use iov_iter_kvec()")
0472e47660 ("SUNRPC: Convert socket page send code to use iov_iter()")

If it is caused by NUMA, why only commit 0472e47660 throughput is decreased? The filesystem we test is NFS, commit 0472e47660 is related with the network, could you help to check if have any other clues for the regression. Thanks.

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Zhengjun Xing