Date: Sun, 25 Nov 2007 14:41:35 -0600 (CST) From: Stephen Montgomery-Smith <stephen@math.missouri.edu> To: Robert Watson <rwatson@freebsd.org> Cc: binto <binto@triplegate.net.id>, freebsd-hackers@freebsd.org, Girwatson@freebsd.org Subject: Re: Before & After Under The Giant Lock Message-ID: <20071125143546.V6583@cauchy.math.missouri.edu> In-Reply-To: <20071125110116.U63238@fledge.watson.org> 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>
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On Sun, 25 Nov 2007, Robert Watson wrote: > ........................ > In FreeBSD 8, I expect we'll see a continued focus on both locking > granularity and improving opportunities for kernel parallelism by better > distributing workloads over CPU pools. This is important because the number > of cores/chip is continuing to increase dramatically, so MP performance is > going to be important to keep working on. That said, the results to date > have been extremely promising, and I anticipate that we will continue to find > ways to better exploit multiprocessor hardware, especially in the network > stack. > I just want to add my 2 cents, that my recent experience with FreeBSD MP has been extremely positive. I tend to use highly CPU bound MP programs, typically lots and lots of floating point operations. It used to be that Linux beat FreeBSD hands down - now FreeBSD seems to have a slight edge! Basically my program runs about twice as fast when I run two threads as opposed to one - I cannot see doing any better than that! (Also when I run 4 threads with 2 cpus, each with hyperthreading, it goes 2.5 to 3 times faster - surprising since hyperthreading gets quite bad press for its performance improvements - I should add that Linux didn't do at all well at taking advantage of hyperthreading, running at the same speed as with 2 threads.) Stephen
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