[haiku-bugs] Re: [Haiku] #10454: New scheduler: substantial performance drop
- From: "pdziepak" <trac@xxxxxxxxxxxx>
- Date: Thu, 06 Feb 2014 03:25:32 -0000
#10454: New scheduler: substantial performance drop
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Reporter: stippi | Owner: pdziepak
Type: task | Status: in-progress
Priority: high | Milestone: R1
Component: System/Kernel | Version: R1/Development
Resolution: | Keywords:
Blocked By: 10487 | Blocking:
Has a Patch: 0 | Platform: All
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Comment (by pdziepak):
There was a delay before thread migration and effect of that migration
becoming visible in the load statistics. That caused scheduler in some
circumstances to migrate virtually all active threads to a single core
(the best fit at that specific moment) then, after updating load
statistics, the scheduler would realize that there is an overloaded core
and migrate most of the active threads to a single core that currently is
the best fit. Basically, this would cause each core to be overloaded for a
short period of time while the others are idle. Average load would look
like none of the cores reaches 100% load.
The situation will eventually stabilize as load statistics updates were
not synchronized in any way with thread migration and that's why the
problem doesn't significantly affect long lived threads (e.g. that
WonderBrush prototype).
Anyway, hrev46824 should make things at least a bit better.
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Ticket URL: <https://dev.haiku-os.org/ticket/10454#comment:12>
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