Date: Sat, 21 Jun 2003 02:47:42 +0100 (BST) From: =?iso-8859-1?q?RMH?= <rmhlldr@yahoo.co.uk> To: current@freebsd.org Subject: SMP & CPU_SUSP_HLT Message-ID: <20030621014742.13635.qmail@web21505.mail.yahoo.com>
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Hello gentlemen, it seems CPU_SUSP_HLT does nothing for SMP kernels. i386/i386/machdep.c: #ifdef SMP static int cpu_idle_hlt = 0; #else static int cpu_idle_hlt = 1; #endif It's noted that when enabled it will result in about 4.2% loss in performance while doing buildworld. I haven't checked with that, but I tested single-threaded applications to suffer for about 2%, what shouldn't be a big difference. Beyond power consumption, suspend on HLT may solve some overheating issues common for multiprocessor systems. At least, it does so in my case. I suggest to remove #ifdef SMP, and place a warning into NOTES. Let people decide. --- Regards, Rhett ________________________________________________________________________ Want to chat instantly with your online friends? Get the FREE Yahoo! Messenger http://uk.messenger.yahoo.com/
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