Eric Saxe wrote: > Hi Aubrey, > > One concern I have looking ahead, is around a similar issue to what we > ran into with the P-states...that when the tool first starts, the > initial state is unknown. For P-states, we get the initial > state through > the kstats...but for c-states we dont...and so that first > interval until > we make a state transition may be wrong...which is what I was > suspecting could be wrong with what I was seeing. Granted, these > state changes happen fairly frequently now...but as we support deeper > states, one could imagine that a processor would (hopefully) spend > quite a bit of time in a given state. I'm wondering if we should > provide a > way via the > kstats to get the CPU's current idle state... Thoughts? > It's different from P-state, I think. P-state will not change when we get P-state initial state To get the current idle state, CPU must be in C0. So if it's in C1, the obtaining changed it. So I think we can just ignore the initial gap. It is not bigger than 10ms. As for the default and reasonable sampling period, it's less than 0.2%. What do you think? ;-)
Thanks, -Aubrey > Eric Saxe wrote: >> Thanks Aubrey, >> >> I was out of town Thursday and Fri, and I didn't get a chance to try >> your changes... I'll let you know if it rectifies the issue I was >> seeing... >> >> -Eric >> >> Li, Aubrey wrote: >> >>> Li, Aubrey wrote: >>> >>> >>> >>>> I failed to replicate this issue on my side. >>>> But from my point of view, we didn't do anything wrong. >>>> So, is the following patch acceptable for this bug? >>>> ====================================================== >>>> diff -r 2fb476052291 usr/src/cmd/powertop/display.c >>>> --- a/usr/src/cmd/powertop/display.c Tue Feb 12 11:55:53 2008 -0800 >>>> +++ b/usr/src/cmd/powertop/display.c Tue Feb 19 23:08:25 2008 +0800 >>>> @@ -185,6 +185,9 @@ void show_cstates(double interval) >>>> >>>> for (i=0; i< g_ncpus; i++) >>>> total_c1 += cstate_info[i].total_time; >>>> + >>>> + if (total_c1 > interval * g_ncpus) >>>> + total_c1 = interval * g_ncpus; >>>> >>>> print(cstate_window, 0, 0, "%s", "Cn\t\t\tAvg residency\n"); >>>> sprintf(c, "C0 (cpu running)\t\t(%.1f%%)\n", >>>> ======================================================= >>>> >>>> >>> I committed this patch since no objection. >>> >>> Thanks, >>> -Aubrey >>> _______________________________________________ >>> tesla-dev mailing list >>> tesla-dev at opensolaris.org >>> http://mail.opensolaris.org/mailman/listinfo/tesla-dev >>> >>> >> >> _______________________________________________ >> tesla-dev mailing list >> tesla-dev at opensolaris.org >> http://mail.opensolaris.org/mailman/listinfo/tesla-dev
