Date: Tue, 28 Feb 2006 10:54:44 -0600 (CST) From: Sergey Babkin <babkin@verizon.net> To: David Malone <dwmalone@maths.tcd.ie>, Vlad GALU <vladgalu@gmail.com> Cc: freebsd hackers <freebsd-hackers@freebsd.org> Subject: Re: Re: Fastest timecounter ? Message-ID: <15896416.1141145684582.JavaMail.root@vms061.mailsrvcs.net>
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>From: David Malone <dwmalone@maths.tcd.ie> >The TSC is always fastest, but unfortunately under some circumstances >it can't be trusted (if your CPU has throttle modes to save power >or on some SMP systems where the two TSCs in each CPU give different >values). If I remember correctly, all the SMP CPUs on the same bus should give the same values (since they are synchronized and reset from the same signals). The discrepancy may appear on machines with multiple bridged front-side buses, essentially the NUMA machines (such as those with over 4 Intel CPUs). -SB
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