On Monday, February 24, 2014 08:29:30 AM Tuukka Tikkanen wrote: > This set of patches makes some minor changes to menu governor and the poll > idle state. > > Patch 1 is simply a rename of a variable to make the name better represent > the contained information. > > Patch 2 fixes calculating actual residency in cases where the entered state > is different from the state decided by the menu governor. > > Patch 3 makes sure the menu governor timer coefficients are not updated > with values that might cause a coefficient to reach a value greater than > unity. > > Patch 4 fixes calculation actual residency in cases where the entered state > does not support measuring residency. In such cases the residency time > is taken from time remaining until next timer expiry. The timer is expected > to go off at the start of exit latency, not after it. Therefore the exit > latency must not be substracted from the assumed value. > > Patch 5 moves the performance multiplier based comparison out of the state > selection loop by changing it into a latency requirement. This allows > using a generic state selection function accepting only (duration, latency) > tuple as input. The change is possible by noting that performance multiplier > is used only to check for a minimum predicted idle duration to exit latency > ratio. As predicted idle duration is a constant for the loop, the maximum > allowed latency can be calculated outside of the loop. > > Patch 6 prevents using negative values from tick_nohz_get_sleep_length() > in the menu governor. If unchecked, the negative values are used as huge > unsigned values. Negative values occur fairly often (e.g. on x86_64 I've > seen this happen several times per minute) on a busy system, allowing > the deepest state to win the selection while the shallowest should be picked. > > Patch 7 adds CPUIDLE_FLAG_TIME_VALID to poll_idle. I do not know of any > platfrom where cpu_relax() would break ktime_get() and in fact poll_idle > uses ktime_get itself. > (Note: poll_idle updates dev->last_residency for some reason. Does it ever > get called without going through cpuidle_enter_state, which will overwrite > the value? Even if some state redirects to this state, the call will > eventually return to the framework. The redundant time measurement could > be removed, unless there is some obscure way of getting called on some > platform that I am unable to figure out.) > > Tuukka Tikkanen (7): > Cpuidle: rename expected_us to next_timer_us in menu governor > Cpuidle: Use actual state latency in menu governor > Cpuidle: Ensure menu coefficients stay within domain > Cpuidle: Do not substract exit latency from assumed sleep length > Cpuidle: Move perf multiplier calculation out of the selection loop > Cpuidle: Deal with timer expiring in the past > Cpuidle: poll state can measure residency > > drivers/cpuidle/driver.c | 2 +- > drivers/cpuidle/governors/menu.c | 85 > ++++++++++++++++++++++++-------------- > 2 files changed, 54 insertions(+), 33 deletions(-)
I'm queuing this series up for 3.15. It looks like at least some of these patches should go into 3.14 and -stable, but for that I'd need some references like links to bug reports or documented reproducibility (on what hardware, what it takes to reproduce etc.). Thanks! -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
