lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 1 Sep 2008 12:10:43 -0700 (PDT) From: Linus Torvalds <torvalds@...ux-foundation.org> To: Thomas Gleixner <tglx@...utronix.de> cc: Larry Finger <Larry.Finger@...inger.net>, LKML <linux-kernel@...r.kernel.org>, "Rafael J. Wysocki" <rjw@...k.pl>, Alok Kataria <akataria@...are.com>, Michael Buesch <mb@...sch.de> Subject: Re: Regression in 2.6.27 caused by commit bfc0f59 On Mon, 1 Sep 2008, Thomas Gleixner wrote: > > Hmm. Haven't seen that before, but if confirms what I guessed from > your previous dmesg information. I wonder why you did not observe > strange behaviour with older kernel versions. x86-32 never used the PM_TIMER for frequency estimation, it only ever used the PIT. See the old "native_calculate_cpu_khz()" in tsc_32.c that you deleted in favor of the (imho inferior) x86-64 version. How about: - taking the old 32-bit code, and using it to initially _just_ estimate the TSC speed. That code was stable and pretty much guaranteed to work reasonably well on all machines. It retries the timings three times, and picks the best one. - Then, _after_ you already have a pretty good estimation for TSC, you can use _that_ to then get the HPET and/or PM_TIMER version (and not use the PIT at all for those calibrations) - and if the PM_TIMER one is too far off, just throw it away. We know the PIT is a lot more trustworthy than the PM_TIMER. Hmm? Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists