On 11/26/12 13:37, Bhavesh Davda wrote: >> On 11/16/12 18:41, Frank Rowand wrote: >>> On 11/16/12 18:31, Frank Rowand wrote: >>> >>> < snip > >>> >>>> I graphed the results with the msec data and with the >>>> nanosecond timestamps for an artificial test (two test runs for >>>> each case): >>>> >>>> nanosecond: junk7.gif junk10.gif msec: junk8_d.gif >>>> junk9_d.gif >>>> >>>> The cyclictest latency disruptions seem more visible to me in >>>> the nanosecond data graphs. But that is just a first >>>> impression without playing around with a lot of different data >>>> sets. >>> >>> John, Bhavesh, >>> >>> OK, so after all of that, I'm going on vacation for a week. I >>> hope the rest of you are taking some time off too. >> >> I'm back... Bhavesh, have you had a chance to think about my last >> several emails (my comments on your latest patch, my proposed >> patch, and the email I'm responding to)? Any comments? > > Hello Frank. Welcome back. I was out for the long weekend and am just > getting back in the swing of things too, so sorry about the delay. > > I do have real use cases for this "outlier" mode, that I've used > effectively to identify sources of high latencies of cyclictest > running in a Linux-rt kernel based VM on our VMware ESXi hypervisor. > The patterns in the outliers, for various thresholds (e.g. 50 us) > have helped me identify timers and callbacks in the hypervisor kernel > (vmkernel) which have caused time to be "stolen" away from scheduling > the virtual CPUs of the VM to do various housekeeping tasks, and to > either move those timers out to other physical CPUs or to limit the > time spend in those timers and callbacks to have a smaller impact on > the cyclictest latencies. > > I'm hoping that others in the community find similar uses of this > "outlier" feature of cyclictest. > > That said, I realize that not every use cases might fit my exact > mould and might require either different formatting, or different > granularities of the "outliers" output. So I'm open to suggestions in > that regard. > > I'm going to respond to your proposed patch next. > > Thanks > > - Bhavesh ping.... Thanks, Frank -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
