Date: Thu, 27 Apr 2000 10:09:47 -0600 From: Steve Passe <smp@csn.net> To: James Housley <jim@thehousleys.net> Cc: freebsd-smp@FreeBSD.ORG Subject: Re: hlt instructions and temperature issues Message-ID: <200004271609.KAA24711@Ilsa.StevesCafe.com> In-Reply-To: Your message of "Thu, 27 Apr 2000 11:57:49 EDT." <3908637D.FA57D436@thehousleys.net>
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Hi, > Luoqi Chen wrote: > > > > Index: swtch.s > > =================================================================== > > RCS file: /home/ncvs/src/sys/i386/i386/swtch.s,v > > retrieving revision 1.91 > > diff -u -r1.91 swtch.s > > --- swtch.s 2000/03/29 06:15:38 1.91 > > +++ swtch.s 2000/04/27 15:31:11 > > @@ -258,9 +258,14 @@ > > > > ENTRY(default_halt) > > sti > > -#ifndef SMP > > - hlt /* XXX: until a wakeup IPI */ > > +#ifdef SMP > > +#ifdef CHEAP_TPR > > + movl $0, lapic_tpr > > +#else > > + andl $~APIC_TPR_PRIO, lapic_tpr > > +#endif /** CHEAP_TPR */ > > #endif > > + hlt > > ret > > > I applied this patch to my 3.4-STABLE SMP cvs's yesterday afternoon. > According to healthd my temps were 44.5 and 38.5 for the CPUs. After > rebooting they cooled down to 32.0 and 30.0. > > I guess the next question is, "Is this seriously impacting > performance?" Personaly a small hit is okay. My experience is yes, we used to have the hlt instruction, but added the #ifdef and XXX comment after we noticed bizarre behaviour where CPU's remained stalled when there were processes to run. My 2 previous mails describe the reasons so I won't repeat them again. (We're playing dueling mailings here, the thread is a little scewed...). Try a buildworld both ways to tell the tale. If you could send me a few lines about how to install healthd on my 4way I'll try to find time to do the same. (last time I tried to use the MB monitors under SMP I got nowhere...) -- Steve Passe | powered by smp@csn.net | Symmetric MultiProcessor FreeBSD To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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