On 5/30/2019 10:00 AM, Trond Myklebust wrote:
Hi Xing,

On Thu, 2019-05-30 at 09:35 +0800, Xing Zhengjun wrote:
Hi Trond,

On 5/20/2019 1:54 PM, kernel test robot wrote:
Greeting,

FYI, we noticed a 16.0% improvement of fsmark.app_overhead due to
commit:


commit: 0472e476604998c127f3c80d291113e77c5676ac ("SUNRPC: Convert
socket page send code to use iov_iter()")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git
master

in testcase: fsmark
on test machine: 40 threads Intel(R) Xeon(R) CPU E5-2690 v2 @
3.00GHz with 384G memory
with following parameters:

        iterations: 1x
        nr_threads: 64t
        disk: 1BRD_48G
        fs: xfs
        fs2: nfsv4
        filesize: 4M
        test_size: 40G
        sync_method: fsyncBeforeClose
        cpufreq_governor: performance

test-description: The fsmark is a file system benchmark to test
synchronous write workloads, for example, mail servers workload.
test-url: https://sourceforge.net/projects/fsmark/



Details are as below:
-----------------------------------------------------------------
--------------------------------->


To reproduce:

          git clone https://github.com/intel/lkp-tests.git
          cd lkp-tests
          bin/lkp install job.yaml  # job file is attached in this
email
          bin/lkp run     job.yaml

===================================================================
======================
compiler/cpufreq_governor/disk/filesize/fs2/fs/iterations/kconfig/n
r_threads/rootfs/sync_method/tbox_group/test_size/testcase:
    gcc-7/performance/1BRD_48G/4M/nfsv4/xfs/1x/x86_64-rhel-
7.6/64t/debian-x86_64-2018-04-03.cgz/fsyncBeforeClose/lkp-ivb-
ep01/40G/fsmark

commit:
    e791f8e938 ("SUNRPC: Convert xs_send_kvec() to use
iov_iter_kvec()")
    0472e47660 ("SUNRPC: Convert socket page send code to use
iov_iter()")

e791f8e9380d945e 0472e476604998c127f3c80d291
---------------- ---------------------------
         fail:runs  %reproduction    fail:runs
             |             |             |
             :4           50%           2:4     dmesg.WARNING:at#for
_ip_interrupt_entry/0x
           %stddev     %change         %stddev
               \          |                \
    15118573 ±  2%     +16.0%   17538083        fsmark.app_overhead
      510.93           -22.7%     395.12        fsmark.files_per_sec
       24.90           +22.8%      30.57        fsmark.time.elapsed_
time
       24.90           +22.8%      30.57        fsmark.time.elapsed_
time.max
      288.00 ±  2%     -
27.8%     208.00        fsmark.time.percent_of_cpu_this_job_got
       70.03 ±  2%     -
11.3%      62.14        fsmark.time.system_time


Do you have time to take a look at this regression?

 From your stats, it looks to me as if the problem is increased NUMA
overhead. Pretty much everything else appears to be the same or
actually performing better than previously. Am I interpreting that
correctly?
The real regression is the throughput(fsmark.files_per_sec) is decreased by 22.7%.

If my interpretation above is correct, then I'm not seeing where this
patch would be introducing new NUMA regressions. It is just converting
from using one method of doing socket I/O to another. Could it perhaps
be a memory artefact due to your running the NFS client and server on
the same machine?

Apologies for pushing back a little, but I just don't have the
hardware available to test NUMA configurations, so I'm relying on
external testing for the above kind of scenario.

Thanks for looking at this.  If you need more information, please let me
know.
Thanks
   Trond


--
Zhengjun Xing

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