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Re: [Bug 1358949] Re: arm64 iperf performance suboptimal

 

On Tue, Aug 19, 2014 at 4:56 PM, Joseph Salisbury
<joseph.salisbury@xxxxxxxxxxxxx> wrote:
> Can you also send this patch to the Ubuntu kernel-team mailing list for
> review?

https://lists.ubuntu.com/archives/kernel-team/2014-August/047895.html

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https://bugs.launchpad.net/bugs/1358949

Title:
  arm64 iperf performance suboptimal

Status in “linux” package in Ubuntu:
  Triaged

Bug description:
  [Impact]
  The copy_{to,from}_user implementations in the Ubuntu kernel are suboptimal. Optimized implementations have been submitted upstream and have shown a significant improvement in network performance.

      Iperf performance increase:
                  -l (size)               1 core result
      Optimized   64B                     44-51Mb/s
                  1500B                   4.9Gb/s
                  30000B                  16.2Gb/s
      Original    64B                     34-50.7Mb/s
                  1500B                   4.7Gb/s
                  30000B                  14.5Gb/s

  [Test Case]
  Generate traffic from one node to another using iperf (see above for config).

  [Regression Risk]
  These functions are obviously used heavily throughout the kernel, so a defect here could have significant impact. This risk is mitigated by using an implementation heavily based on the linaro string libraries (which are used in other places already, e.g. glibc), and through active testing of this patch on real hardware using a trusty-kernel base.

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References