Date: Wed, 07 Nov 2001 11:44:11 -0800 (PST) From: John Baldwin <jhb@FreeBSD.org> To: Kevin Coffman <kwc@citi.umich.edu> Cc: freebsd-smp@freebsd.org Subject: RE: magic switch? Message-ID: <XFMail.011107114411.jhb@FreeBSD.org> In-Reply-To: <20011107194120.045EA207CF@citi.umich.edu>
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On 07-Nov-01 Kevin Coffman wrote: > > I've looked around a bit, but haven't seen this. Is there a "magic > switch" that I can flip to disable all but one processor in an > SMP-enabled kernel on an SMP machine? We'd like to do some > measurements comparing performance of an application running on one cpu > vs. two cpus, without the need to reboot between a UP kernel and SMP > kernel. Is this possible? It's certainly possible, but it's not implemented right now AFAIK. :) I think you could just modify smp_active via a sysctl. However, I'm not sure if the CPU's would resume when you set smp_active back to 1 after clearing it. -- John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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