Re: Before & After Under The Giant Lock

On Nov 25, 2007 12:05 PM, Christopher Chen <muffaleta@xxxxxxxxx> wrote:
On Nov 25, 2007 3:13 AM, Robert Watson <rwatson@xxxxxxxxxxx> 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@xxxxxxxxx>
"I want the kind of six pack you can't drink."
-- Micah
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Relevant Pages

  • Re: Before & After Under The Giant Lock
    ... improvements in parallelism through removing Giant. ... In FreeBSD 7, the focus ... libthread after all? ...
    (freebsd-hackers)
  • Re: Before & After Under The Giant Lock
    ... In FreeBSD 7, the focus was on improving parallelism rather than removing Giant, with improvements in locking primitives, the scheduler, and lock granularity. ... At some point during the 6.x days, it was considered advantageous to use libthr when running MySQL. ...
    (freebsd-hackers)