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Date: Sat, 14 Aug 2010 07:44:07 -0400
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Subject: Re: Cygwin speed difference on multiple cores -vs- single-core?
From: mike marchywka <marchywka AT gmail DOT com>
To: cygwin AT cygwin DOT com
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On 8/13/10, Andy Nicholas <> wrote:

> The scripts we're using form the basis of a build system to invoke GCC and
> an
> assembler lots of times throughout a directory tree of a few thousand items.

You can end up spending all your time chasing include paths that isn't
hard to do.

> to use multi-threaded builds. When running each testing method, the CPUs are
> barely loaded at all (10%, maybe) and there's almost no I/O that registers.
Is the disk light on ? This is almost always an indication of blocking
for something. Check task manager page faults for example.


> Btw, I don't think the issue is I/O. The disk I'm using is an SSD (OCZ
> Vertex
> 2) which is fairly fast. But, the results repeat even if I try a regular
> 7200
> RPM hard drive.

I should add this to my manifesto against adjectives along with
fast snail comments. 7200rpm=720/6 revs-per-second=120rps.
This puts rotation time somewhere in millisecond range. Track to
track seeks won't subtract from that. Memory of course is in
nanosecond range, 1e6 times faster.
The issue is likely
to be buffering strategies and syncing.


>
> Yeah, weird.
>
> andy
>
>
>
>
>
>
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-- 
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