Date: Thu, 6 Jan 2005 19:36:49 +0000 (GMT) From: Robert Watson <rwatson@freebsd.org> To: stheg olloydson <stheg_olloydson@yahoo.com> Cc: freebsd-performance@freebsd.org Subject: Re: Benchmark: NetBSD 2.0 [allegedly] beats FreeBSD 5.3 in server performance Message-ID: <Pine.NEB.3.96L.1050106192740.98115A-100000@fledge.watson.org> In-Reply-To: <20050106174100.18034.qmail@web53908.mail.yahoo.com>
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On Thu, 6 Jan 2005, stheg olloydson wrote: > it was said by Phil Brennan: > > >What about the context switch time? Are there any plans to improve > >this, and also to reduce the number of context switches needed? > > See Robert Watson's reply to this thread. An unfortunate number of > problems exist in threading and scheduling. Most are well-understood and > are being worked on and 5.4 should see measurable improvement. > Personally, I am more concerned with network and scheduler perfomance. > I know the former is being addressed, but I don't hear anything about > how work on SCHED_ULE is progressing. FWIW, one of the reasons that there hasn't been as much interest in SCHED_ULE lately is likely that several of the features previously only present in SCHED_ULE are now also present in SCHED_4BSD -- for example, making more effective uses of IPIs in reducing latency during inter-process communication across processors. While SCHED_ULE does contain a number of interesting things not present in SCHED_4BSD, the 4BSD scheduler has hardly gone un-improved in that time. However, Jeff Robserson does seem to have picked up recently on both VFS SMP locking and ULE. The scheduler tracing and visualization tools he committed a couple of weeks ago are really quite neat tools. Robert N M Watson
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