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Date:      Sun, 25 Nov 2007 12:09:20 -0800
From:      "Christopher Chen" <muffaleta@gmail.com>
To:        "Robert Watson" <rwatson@freebsd.org>
Cc:        freebsd-hackers@freebsd.org
Subject:   Re: Before & After Under The Giant Lock
Message-ID:  <7bc80d500711251209p3bd78bc0leb37d4cb85f677f3@mail.gmail.com>
In-Reply-To: <7bc80d500711251205w1a74b649mc3bd374545c1012c@mail.gmail.com>
References:  <474830F9.90305@zirakzigil.org> <6eb82e0711240638g2cc1e54o1fb1321cafe8ff9f@mail.gmail.com> <1188.202.127.99.4.1195957922.squirrel@webmail.triplegate.net.id> <20071125110116.U63238@fledge.watson.org> <7bc80d500711251205w1a74b649mc3bd374545c1012c@mail.gmail.com>

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On Nov 25, 2007 12:05 PM, Christopher Chen <muffaleta@gmail.com> wrote:
> On Nov 25, 2007 3:13 AM, Robert Watson <rwatson@freebsd.org> wrote:
> > At this point, Giant is gradually becoming a lock around the tty, newbus, usb,
> > and msdosfs code, and we're largely at diminishing returns in terms of making
> > improvements in parallelism through removing Giant.  In FreeBSD 7, the focus
> > was on improving parallelism rather than removing Giant, with improvements in
> > locking primitives, the scheduler, and lock granularity.  For example, most of
> > the improvement in MySQL performance in FreeBSD 7 can be put down to a small
> > number of changes:
> >
> > - Conversion to 1:1 threads from M:N threads.
>
> Dear Robert:
>
> I enjoyed reading your overview of changes from FreeBSD 6 to 7 with
> regards to MP scalability, but I am a bit confused over this
> point--Doesn't the user still have the choice between libthread, which
> is M:N, and libthr, which is 1:1?
>
> At some point during the 6.x days, it was considered advantageous to
> use libthr when running MySQL. Has the project decided to go with
> libthread after all?
>
> Perhaps we're talking about entirely different things.

My apologies. I re-read your statement and it makes sense now.

I thought you were saying we were converting from 1:1 to M:N.

Sorry for any confusion!

-- 
Chris Chen <muffaleta@gmail.com>
"I want the kind of six pack you can't drink."
-- Micah



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