Hi Yawei Wu,
The root of the confusion is the fact the cpu meter is reporting the cumlative cpu_time stat from libvirt. This libvirt counter is reset when the associated qemu process is restarted (an artifact of how cpuacct works). So when you stop/start or suspend/resume, a fresh qemu process is sparked up, then the cumulative time is reset. Thanks for bringing this up, as it has implications as to how we meter CPU time and utilization[1]. We may need to start metering the delta between CPU times on subsequent polling cycles, instead of using a cumulative meter (dealing with the edge case where the instance has been restarted within a polling period). Cheers, Eoghan [1] https://review.openstack.org/14921 > I am still testing ceilometer now. I am confused about the meter > volume > in the mongodb. Let's talk about cpu usage. > > After I create and boot a vm named vm_1, meter data record about cpu > usage will be inserted into db in cycle(default 10 minutes). For > example,the 'counter_volume' of the first record is '52060000000',and > the second one is '123890000000'. > > 1) '123890000000' nanoseconds means '123.89' seconds or two > minutes,it > seem like to be 1238.9 seconds actually, is there something wrong ? > > 2) If I never reboot or suspend vm_1, will the 'counter_volume' of > cpu > usage record increase all the time ? Just like '8 minutes' -> '18 > minutes' -> '28 minutes' ? > > 3) If I reboot or suspend vm_1, I find that the 'counter_volume' of > cpu > usage record will count from zero. Just like '8 minutes' -> '18 > minutes' > -> '28 minutes' [-> '0 minutes'] ->'5 minutes' -> '15 minutes'. Does > it > mean that 'counter_volume' just represents how long has vm_1 been > booted > up ? > > 4) This one is about Web API. I find that "GET > /v1/resources/(resource)/meters/(meter)/volume/sum" just return the > sum > value of all the cpu 'counter_volume', like '8 minutes' + '18 > minutes'. > Is it reduplicate ? > > 5) If I want to know how long has vm_1's cpu been used yesterday, how > can I do ? > > It seems like that I have too many questions.. > > Thank you very much ! > > > ----------------------- > Yawei Wu > Dalian Hi-Think Computer Technology,Corp. > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp > _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
