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  1. Traffic Server
  2. TS-3753

High CPU iowait with null-transform on a content from the cache.

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    Details

    • Type: Bug
    • Status: Open
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: 5.3.0
    • Fix Version/s: sometime
    • Component/s: Plugins, TS API
    • Labels:
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      Description

      Hi,

      I'm trying to calculate some stats doing null-transform on a content served from the cache. However, I observed high CPU iowait when doing this. I isolated the issue to be related to the case when we do transformation on a content served from the cache. Please, see the attached few lines patch which when applied to the null-transform plugin causes high CPU iowait. Note also that when I tried the original null-transform plugin I didn't observe such increased CPU iowait. Please, see also the attached picture where you can see the increased CPU iowait (between 15:30 and 16:30 in red) when I started the test with null-transform from cache.

        Attachments

        1. null-transform-cache.patch
          1 kB
          Pavel Vazharov
        2. usi.png
          52 kB
          Pavel Vazharov

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              • Assignee:
                Unassigned
                Reporter:
                pavel_v Pavel Vazharov
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                • Created:
                  Updated: