On Fri, Aug 20, 2010 at 8:55 AM, jean-philippe francois <jp.francois@xxxxxxxxxx> wrote: > Hi, > > Please correct me if I am sending this to the wrong list. LKML is better for this issue. Added. Lin Ming > > I would like to debug the following issue, which I suspect is related > to cpu losing track of time when going idle. > > When I run the following script : > > #!/bin/bash > # set hwclock to system clock to start > # the log file with the same time > hwclock -w > #start with a fresh logfile > touch clocktest.log > echo START > clocktest.log > while [[ true ]] > do > systime=$(date) > hwtime=$(hwclock -r) > echo "$systime | $hwtime" >> clocktest.log > sleep 20 > done > > Expected output : > On each line, the system time (left) and hardware time (right) > should be roughly the same. Time delta between each line should be > around 20 seconds > > Observed output : > This is an edited version of the real logfile so that it fits on one > line. the date was removed. > START > 15:09:43 (UTC+0200) | 15:09:44 CEST -0.500555 secondes > 15:10:04 (UTC+0200) | 15:10:05 CEST -1.001562 secondes > 15:10:25 (UTC+0200) | 15:10:26 CEST -0.985944 secondes > 15:10:46 (UTC+0200) | 15:15:46 CEST -0.032792 secondes <-- 5 minute lag ! > 15:11:06 (UTC+0200) | 15:16:07 CEST -0.985926 secondes > 15:11:27 (UTC+0200) | 15:16:28 CEST -1.001539 secondes > 15:11:48 (UTC+0200) | 15:16:49 CEST -0.985969 secondes > 15:12:09 (UTC+0200) | 15:17:10 CEST -0.985977 secondes > 15:12:30 (UTC+0200) | 15:17:31 CEST -1.001544 secondes > 15:12:51 (UTC+0200) | 15:17:52 CEST -0.985920 secondes > 15:13:12 (UTC+0200) | 15:18:13 CEST -0.985939 secondes > 15:13:33 (UTC+0200) | 15:18:34 CEST -1.001581 secondes > 15:13:54 (UTC+0200) | 15:18:55 CEST -0.985917 secondes > 15:14:15 (UTC+0200) | 15:29:15 CEST -0.079685 secondes <-- add > another 10 minute > 15:14:35 (UTC+0200) | 15:29:36 CEST -1.001568 secondes > 15:14:56 (UTC+0200) | 15:29:57 CEST -0.985952 secondes > > As you can see, after 20 minutes without touching the computer, the > system time is late by 15 minutes. > This was tested on ubuntu 10.04 with a 2.6.32 "vanilla" kernel where > "vanilla" means ubuntu packaged > upstream kernel closest to the distribution shipped kernel. > > How can I debug and possibly fix this issue ? > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
