Threadscope reporting that nothing is happening (MUT or GC) for ~2 seconds

[Patrick Palka]

Mystery solved -- the gap is likely the RTS waiting on an external process
(the linker) to exit.


On Tue, Jul 30, 2013 at 3:34 PM, Patrick Palka <patrick at parcs.ath.cx> wrote:

> Hi,
>
> I'm analyzing the performance of my parallel --make branch of GHC (
> https://github.com/parcs/ghc/tree/cherry-picking if anyone is interested)
> by compiling the Cabal repository in parallel, using two capabilities.
>
> I'm seeing very strange results from Threadscope: at some point during the
> compile, absolutely no work is being performed on any HEC for about 2
> seconds. How do I interpret this kind of behavior? What does it mean?
>
> Relevant screenshot: http://i.imgur.com/uDQk9zG.png
>
> Patrick
>
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