Messages in this thread | | | Date | Thu, 2 May 2013 12:11:50 -0700 | Subject | Re: [RFC PATCH] power: Add option to log time spent in suspend | From | Colin Cross <> |
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On Thu, May 2, 2013 at 11:58 AM, John Stultz <john.stultz@linaro.org> wrote: > On 05/02/2013 11:29 AM, Colin Cross wrote: >> >> On Thu, May 2, 2013 at 5:27 AM, Pavel Machek <pavel@ucw.cz> wrote: >>> >>> >>>> dmesg is not the solution, it's not a stable api, it would require >>>> constant parsing to make sure you didn't miss data before it fell out >>>> of the ringbuffer, and sched_clock often does not (and should not) >>>> tick during suspend, so printk times don't show the time spent >>>> suspended. >>> >>> If timing info printed is invalid, that should be fixed. >> >> It's not invalid, its just not measuring the time that is useful here. >> printk is measuring something similar to (but not exactly the same >> as) CLOCK_MONOTONIC, but this is measuring something similar to >> CLOCK_BOOTTIME. > > > One thing I'm curious about with this patch, since we measure and keep track > of suspend time in the timekeeping core, there may be enough justification > to adding this sort of debugging info the timekeeping core itself. > > Although what is being tracked with this driver isn't just total time in > suspend, but looks like more of a logarithmic histogram of suspend times. Is > there any context you can provide as to why that particular format was > chosen (which would could be added to help improve the commit message)?
The idea was to keep a minimal amount of data while still being able to see how often the device is waking up.
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