Rafael.Vanoni wrote:
> Li, Aubrey wrote:
>> tesla-dev-bounces at opensolaris.org wrote:
>>
>>> Aubrey Li wrote:
>>>> [snip]
>>>>>> That is the behavior in the original linux implementation.
>>>>>> Actually there is a mechanism to auto-adjust the ticktime, but it
>>>>>> has been removed to powertop prototype quickly delivered, it
>>>>>> would be great if it can be recovered. Think about the future
>>>>>> tickless kernel, the cpu wakeup times become less, making the
>>>>>> ticktime longer makes more sense if the wakeup events is few in
>>>>>> the current sampling period.
>>>>> So you mean adapting the interval based on the amount of wakeups -
>>>>> i.e few wakeups, higher interval and vice-versa ?
>>>>>
>>>>> I'll have a look at the original code.
>>>>>
>>>> That would be great, thanks, :-)
>>> Ok, the Linux version sets maxsleep (below) to the duration of the
>>> last transition and then sets the interval according to
>>>
>>> if (maxsleep < 5.0)
>>> ticktime = 10;
>>> else if (maxsleep < 30.0)
>>> ticktime = 15;
>>> else if (maxsleep < 100.0)
>>> ticktime = 20;
>>> else if (maxsleep < 400.0)
>>> ticktime = 30;
>>> else
>>> ticktime = 45;
>>>
>>>
>>> There's also
>>>
>>> if (wakeups_per_second < 0)
>>> ticktime = 2;
>>>
>>> How about adding this functionality as the default option, and
>>> fixing the interval if -t is used ?
>>>
>> Sounds great to me.
>
> Cool, here's a patch for these changes.
>
+ last_time =
(((double)cstate_info[longest_cstate].total_time/g_ncpus)/total_events);
I failed to understand what does last_time mean. the front part is the
longest cstate residency per cpu.
why "/total_events" here?
+ if (!user_interval) {
+ if (last_time < 5.0 || total_events/ticktime <
0)
Did you notice the unit of total_time is ns? how big last_time here?
And, is it possible (total_events/ticktime < 0)??
+ ticktime = 2;
+ else if (last_time < 10.0)
+ ticktime = 7;
+ else if (last_time < 50.0)
+ ticktime = 35;
+ else if (last_time < 100.0)
+ ticktime = 75;
+ else
+ ticktime = 100;
These ticktime value looks weird, what are they based?
Thanks,
-Aubrey
