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Observe slow file IO

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Weirong Zhu

21 Oct, 2015 11:15 PM

During last couple days, our build experiences failures from time to time. Investigated a little bit and found that this was due to unexpected slow file IO. It seems there'll be glitch of file IO speed. When it happens, writing a 5M file can take 10 seconds. Before and after the glitch, everything seems to be fine. It just suddenly slows down to almost exact 10 seconds then back to normal. Such glitches causes some test tasks timed out (since it's unexpected). Also, when being assigned the "slow VMs", the overall build time can sometimes double. Any idea?

Thanks,
Weirong

1. Support Staff 1 Posted by Feodor Fitsner on 21 Oct, 2015 11:26 PM

   

   What account/project is that?

   - Feodor

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2. 2 Posted by Weirong Zhu on 21 Oct, 2015 11:27 PM

   

   https://ci.appveyor.com/project/zhuweirong/prajna-rbpft

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3. 3 Posted by Weirong Zhu on 21 Oct, 2015 11:34 PM

   

   For example, below is a good run

    https://ci.appveyor.com/project/zhuweirong/prajna-rbpft/build/0.0.1.300
   

   and we see the following copying phase take 23 seconds

    CopyReleaseBinaries              00:00:23.5608673
   

   However, when we get a "slow VM", such as

   https://ci.appveyor.com/project/zhuweirong/prajna-rbpft/build/0.0.1.298
   

   we see

   CopyReleaseBinaries              00:01:04.6661011
   

   This "CopyReleaseBinaries" phase has no computation, just file copies. The time taken can vary significantly.

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4. Ilya Finkelshteyn closed this discussion on 25 Aug, 2018 02:01 AM.