Date: Sun, 20 Jul 2008 07:06:19 -0700 From: "Murty, Ravi" <ravi.murty@intel.com> To: "Jeremy Chadwick" <koitsu@FreeBSD.org> Cc: freebsd-hackers@freebsd.org, Kris Kennaway <kris@FreeBSD.org>, d@delphij.net Subject: RE: Bug in calcru in he 6.2 and 6.3 kernels Message-ID: <AEBCFC23C0E40949B10BA2C224FC61B007C221BA@orsmsx416.amr.corp.intel.com> In-Reply-To: <20080720135900.GA68132@eos.sc1.parodius.com> References: <AEBCFC23C0E40949B10BA2C224FC61B007A3253D@orsmsx416.amr.corp.intel.com> <48726193.1080807@FreeBSD.org> <48727E37.30700@delphij.net> <487284CA.4050407@FreeBSD.org> <AEBCFC23C0E40949B10BA2C224FC61B007C221B9@orsmsx416.amr.corp.intel.com> <20080720135900.GA68132@eos.sc1.parodius.com>
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Jeremy, thanks. I look forward to switching to ULE in 7.0 and realize that it is a completely new scheduler (I spent some time yesterday looking at it) -- which is my porting effort is much harder than a simple cut and paste. I just wanted to find out if there was something simple I could look at before I spent weeks porting my changes to the scheduler (also I can justify the move to 7.x). I can't figure out why my 8 app threads run so slow -- I am booting the kernel is single user mode with not much else running and my threads do a lot of work and don't really sleep. Thanks Ravi -----Original Message----- From: Jeremy Chadwick [mailto:koitsu@FreeBSD.org]=20 Sent: Sunday, July 20, 2008 6:59 AM To: Murty, Ravi Cc: Kris Kennaway; d@delphij.net; freebsd-hackers@freebsd.org Subject: Re: Bug in calcru in he 6.2 and 6.3 kernels On Sun, Jul 20, 2008 at 06:51:22AM -0700, Murty, Ravi wrote: > Has anyone identified the issue(s) that might be broken in the ULE > scheduler in 6.2? I am running a rather simple test - creates 8 threads > and runs it on an 8 CPU system (not a whole lot running on the system). > When I run it with ULE, it runs slow, very slow sometimes - it's almost > like the threads aren't picked to run. When I switch to 4BSD, things run > fine. I was wondering if there is something I could look at? I realize > it is broken, but I've added lots of stuff to the scheduler (for our > project) which I'd have to migrate to ULE in 7.0. I'd like to figure out > what might be going on in 6.2 before I spend the time to migrate to 7.0. ULE in 7.0 is not the same as in 6.2 -- it was entirely re-written before 7.0 was released. The ULE scheduler in 7.0 is often called "ULE 2.0", to signify that it's not the same ULE scheduler in previous FreeBSD releases. See "New Scheduler: ULE 2.0 / 3.0" here: http://ivoras.sharanet.org/freebsd/freebsd7.html Technical details from the author: http://jeffr-tech.livejournal.com/3729.html The reason the ULE scheduler in 7.0 is not the default scheduler is because the community felt more testing needed to be done. I believe the plan is to have ULE as the default scheduler in 7.1. You should really be running 4BSD on 6.x, and ULE on 7.x (unless you have reason to run 4BSD on 7.x -- and some people do. And no, I don't know the reasons why). --=20 | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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