| 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: Fri, 26 Jun 2009 09:25:04 +0200 From: Ingo Molnar <mingo@...e.hu> To: "Pallipadi, Venkatesh" <venkatesh.pallipadi@...el.com> Cc: linux-kernel@...r.kernel.org, tglx@...utronix.de, hpa@...or.com Subject: Re: [PATCH] x86: tsc based udelay should have rdtsc_barrier * Pallipadi, Venkatesh <venkatesh.pallipadi@...el.com> wrote: > > delay_tsc needs rdtsc_barrier to provide proper delay. > > Output from a test driver using hpet to cross check delay > provided by udelay(). > > Before: > [ 86.794363] Expected delay 5us actual 4679ns > [ 87.154362] Expected delay 5us actual 698ns > [ 87.514162] Expected delay 5us actual 4539ns > [ 88.653716] Expected delay 5us actual 4539ns > [ 94.664106] Expected delay 10us actual 9638ns > [ 95.049351] Expected delay 10us actual 10126ns > [ 95.416110] Expected delay 10us actual 9568ns > [ 95.799216] Expected delay 10us actual 9638ns > [ 103.624104] Expected delay 10us actual 9707ns > [ 104.020619] Expected delay 10us actual 768ns > [ 104.419951] Expected delay 10us actual 9707ns > > After: > [ 50.983320] Expected delay 5us actual 5587ns > [ 51.261807] Expected delay 5us actual 5587ns > [ 51.565715] Expected delay 5us actual 5657ns > [ 51.861171] Expected delay 5us actual 5587ns > [ 52.164704] Expected delay 5us actual 5726ns > [ 52.487457] Expected delay 5us actual 5657ns > [ 52.789338] Expected delay 5us actual 5726ns > [ 57.119680] Expected delay 10us actual 10755ns > [ 57.893997] Expected delay 10us actual 10615ns > [ 58.261287] Expected delay 10us actual 10755ns > [ 58.620505] Expected delay 10us actual 10825ns > [ 58.941035] Expected delay 10us actual 10755ns > [ 59.320903] Expected delay 10us actual 10615ns > [ 61.306311] Expected delay 10us actual 10755ns > [ 61.520542] Expected delay 10us actual 10615ns Nice fix! Ingo -- 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