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Builds are spending lots of time (~4.5%) of CPU just sleeping #2391

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davkean opened this issue Aug 3, 2017 · 4 comments
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Builds are spending lots of time (~4.5%) of CPU just sleeping #2391

davkean opened this issue Aug 3, 2017 · 4 comments
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performance Performance-Scenario-Solution-Open This issue affects solution open performance. Priority:2 Work that is important, but not critical for the release triaged
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VS 17.0

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@davkean
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davkean commented Aug 3, 2017

Trying to speed up design-time builds, and I can see that 4.5% of the CPU is just sleeping (is this spin waiting?):

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Could be related to: #2384.
@davkean
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davkean commented Aug 3, 2017 •
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I can't tell if this is "real" CPU usage or if the thread was really sleeping when PerfView captured. I thought that PerfView sampled whatever the CPU was executing at the time, which would lean to the former.

@davkean davkean mentioned this issue Aug 15, 2017
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davkean commented Aug 15, 2017 •
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In this customer's process, 11% of the build is just calling Sleep: dotnet/project-system#2712:

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@davkean davkean mentioned this issue Sep 6, 2017
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@AndyGerlicher AndyGerlicher added this to the MSBuild 15.6 milestone Nov 6, 2017
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Found this issue occasionally after a PerfView session of my own.
IIRC, this callstack means that thread pool is being hammered with lots of thread creation requests (QueueUserWorkItem, tasks, etc.) that arrive in a short time interval, so yes, #2384 is probably the real deal.

@davkean davkean mentioned this issue Nov 26, 2017
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@panopticoncentral panopticoncentral added the Performance-Scenario-Solution-Open This issue affects solution open performance. label Mar 25, 2020
@panopticoncentral panopticoncentral removed this from the MSBuild 15.6 milestone May 21, 2020
@panopticoncentral panopticoncentral added the Priority:2 Work that is important, but not critical for the release label Mar 23, 2021
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ladipro commented Aug 13, 2021

These sleeps were eliminated in #6678.

@ladipro ladipro closed this as completed Aug 13, 2021
@ladipro ladipro modified the milestones: .NET 6.0, VS 17.0 Dec 9, 2021
@AR-May AR-May added the triaged label Feb 21, 2024
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performance Performance-Scenario-Solution-Open This issue affects solution open performance. Priority:2 Work that is important, but not critical for the release triaged
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@onyxmaster @panopticoncentral @davkean @benvillalobos @AndyGerlicher @ladipro @AR-May