Jason Petersen
2007-Dec-11 18:21 UTC
[Xen-users] Inconsistent and non-monotonic values from ''date''
I''m running ubuntu as a domU on Xen 3.03... Within the dom0, date works as expected (returns the date, no jumps, monotonic increasing). On this particular domU, six consecutive calls to date would return the following: jpetersen@devel:~$ date Tue Dec 11 12:16:46 CST 2007 jpetersen@devel:~$ date Tue Dec 11 12:17:12 CST 2007 jpetersen@devel:~$ date Tue Dec 11 12:16:48 CST 2007 jpetersen@devel:~$ date Tue Dec 11 12:17:15 CST 2007 jpetersen@devel:~$ date Tue Dec 11 12:16:51 CST 2007 jpetersen@devel:~$ date Tue Dec 11 12:17:17 CST 2007 The calls were each made one second apart. (I''d script this using "sleep" within a loop, but the behavior I''m demonstrating breaks sleep). No clue why this is happening; the domU is not running NTP and independent wallclock is turned off (the dom0 is running ntp for me). This is breaking my build system, so any help would be appreciated. I''ve tried running ntp in the domU (with an independent wall clock), but have the same problem. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
jasonmp85
2007-Dec-11 19:37 UTC
[Xen-users] Inconsistent and non-monotonic values from ''date''
I''m running ubuntu as a domU on Xen 3.03... Within the dom0, date works as expected (returns the date, no jumps, monotonic increasing). On this particular domU, six consecutive calls to date would return the following: jpetersen@devel:~$ date Tue Dec 11 12:16:46 CST 2007 jpetersen@devel:~$ date Tue Dec 11 12:17:12 CST 2007 jpetersen@devel:~$ date Tue Dec 11 12:16:48 CST 2007 jpetersen@devel:~$ date Tue Dec 11 12:17:15 CST 2007 jpetersen@devel:~$ date Tue Dec 11 12:16:51 CST 2007 jpetersen@devel:~$ date Tue Dec 11 12:17:17 CST 2007 The calls were each made one second apart. (I''d script this using "sleep" within a loop, but the behavior I''m demonstrating breaks sleep). No clue why this is happening; the domU is not running NTP and independent wallclock is turned off (the dom0 is running ntp for me). This is breaking my build system, so any help would be appreciated. I''ve tried running ntp in the domU (with an independent wall clock), but have the same problem. -- View this message in context: http://www.nabble.com/Inconsistent-and-non-monotonic-values-from-%27date%27-tp14280053p14280053.html Sent from the Xen - User mailing list archive at Nabble.com. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
jim burns
2007-Dec-25 20:34 UTC
Re: [Xen-users] Inconsistent and non-monotonic values from ''date''
On Tue December 11 2007 1:21:04 pm Jason Petersen wrote:> jpetersen@devel:~$ date > Tue Dec 11 12:16:46 CST 2007 > jpetersen@devel:~$ date > Tue Dec 11 12:17:12 CST 2007 > jpetersen@devel:~$ date > Tue Dec 11 12:16:48 CST 2007 > jpetersen@devel:~$ date > Tue Dec 11 12:17:15 CST 2007 > jpetersen@devel:~$ date > Tue Dec 11 12:16:51 CST 2007 > jpetersen@devel:~$ date > Tue Dec 11 12:17:17 CST 2007It looks like you have two separate monotonic sequences - Do you have a multiple core system? It almost looks like they are keeping different offsets to a base time. Wouldn''t know what to do with that, but I''m not surprised it''s happening on Ubuntu. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Jason Petersen
2007-Dec-27 01:53 UTC
Re: [Xen-users] Inconsistent and non-monotonic values from ''date''
I''m not sure what Ubuntu has to do with this (if you like I can probably replicate this problem on any distro, you pick), but two separate monotonic sequences isn''t very useful when they''re interlaced... Apparently turning on CPU pinning fixed the issue (I currently have independent_wallclock on but I think I''ll still be ok with it off). This is an issue with Xen, not any particular distro. --Jason On Dec 25, 2007, at 2:34 PM, jim burns wrote:> On Tue December 11 2007 1:21:04 pm Jason Petersen wrote: >> jpetersen@devel:~$ date >> Tue Dec 11 12:16:46 CST 2007 >> jpetersen@devel:~$ date >> Tue Dec 11 12:17:12 CST 2007 >> jpetersen@devel:~$ date >> Tue Dec 11 12:16:48 CST 2007 >> jpetersen@devel:~$ date >> Tue Dec 11 12:17:15 CST 2007 >> jpetersen@devel:~$ date >> Tue Dec 11 12:16:51 CST 2007 >> jpetersen@devel:~$ date >> Tue Dec 11 12:17:17 CST 2007 > > It looks like you have two separate monotonic sequences - Do you > have a > multiple core system? It almost looks like they are keeping > different offsets > to a base time. Wouldn''t know what to do with that, but I''m not > surprised > it''s happening on Ubuntu. > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
jim burns
2007-Dec-27 02:15 UTC
Re: [Xen-users] Inconsistent and non-monotonic values from ''date''
On Wednesday 26 December 2007 08:53:01 pm Jason Petersen wrote:> I''m not sure what Ubuntu has to do with this (if you like I can > probably replicate this problem on any distro, you pick), but two > separate monotonic sequences isn''t very useful when they''re > interlaced...I''m picking on Ubuntu because of the frequent posts about having to disable /sbin/hwclock on it, and I''ve never seen two separate monotonic sequences reported for any other distro, but feel free to prove me wrong (anyone). _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
jim burns
2007-Dec-27 02:19 UTC
Re: [Xen-users] Inconsistent and non-monotonic values from ''date''
On Wednesday 26 December 2007 08:53:01 pm Jason Petersen wrote:> I''m not sure what Ubuntu has to do with this (if you like I can > probably replicate this problem on any distro, you pick), but two > separate monotonic sequences isn''t very useful when they''re > interlaced...I''m picking on Ubuntu because of the frequent posts about having to disable /sbin/hwclock, and no one has reported two separate monotonic sequences on any other distro, but feel free to prove me wrong (anyone). Makes sense though that cpu pinning would solve the problem. Glad you got it to work. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users