On 27 September 2012 14:34, Viresh Kumar <viresh.ku...@linaro.org> wrote: > This is V2 of my sched_select_cpu() work. > > In order to save power, it would be useful to schedule work onto non-IDLE cpus > instead of waking up an IDLE one. > > To achieve this, we need scheduler to guide kernel frameworks (like: timers & > workqueues) on which is the most preferred CPU that must be used for these > tasks. > > This patchset is about implementing this concept. > > - The first patch adds sched_select_cpu() routine which returns the preferred > cpu which is non-idle. > - Second patch removes idle_cpu() calls from timer & hrtimer. > - Third patch is about adapting this change in workqueue framework. > > Earlier discussions over v1 can be found here: > http://www.mail-archive.com/linaro-dev@lists.linaro.org/msg13342.html > > Earlier discussions over this concept were done at last LPC: > http://summit.linuxplumbersconf.org/lpc-2012/meeting/90/lpc2012-sched-timer-workqueue/ > > Module created for testing this behavior is present here: > http://git.linaro.org/gitweb?p=people/vireshk/module.git;a=summary > > Following are the steps followed in test module: > 1. Run single work on each cpu > 2. This work will start a timer after x (tested with 10) jiffies of delay > 3. Timer routine queues a work... (This may be called from idle or non-idle > cpu) > and starts the same timer again STEP 3 is done for n number of times (i.e. > queuing n works, one after other) > 4. All works will call a single routine, which will count following per cpu: > - Total works processed by a CPU > - Total works processed by a CPU, which are queued from it > - Total works processed by a CPU, which aren't queued from it > > Setup: > ----- > - ARM Vexpress TC2 - big.LITTLE CPU > - Core 0-1: A15, 2-4: A7 > - rootfs: linaro-ubuntu-nano > > Results: > ------- > Without Workqueue Modification, i.e. PATCH 3/3: > [ 2493.022335] Workqueue Analyser: works processsed by CPU0, Total: 1000, > Own: 0, migrated: 0 > [ 2493.047789] Workqueue Analyser: works processsed by CPU1, Total: 1000, > Own: 0, migrated: 0 > [ 2493.072918] Workqueue Analyser: works processsed by CPU2, Total: 1000, > Own: 0, migrated: 0 > [ 2493.098576] Workqueue Analyser: works processsed by CPU3, Total: 1000, > Own: 0, migrated: 0 > [ 2493.123702] Workqueue Analyser: works processsed by CPU4, Total: 1000, > Own: 0, migrated: 0 > > With Workqueue Modification, i.e. PATCH 3/3: > [ 2493.022335] Workqueue Analyser: works processsed by CPU0, Total: 1002, > Own: 999, migrated: 3 > [ 2493.047789] Workqueue Analyser: works processsed by CPU1, Total: 998, > Own: 997, migrated: 1 > [ 2493.072918] Workqueue Analyser: works processsed by CPU2, Total: 1013, > Own: 996, migrated: 17 > [ 2493.098576] Workqueue Analyser: works processsed by CPU3, Total: 998, > Own: 993, migrated: 5 > [ 2493.123702] Workqueue Analyser: works processsed by CPU4, Total: 989, > Own: 987, migrated: 2 > > V1->V2 > ----- > - New SD_* macros removed now and earlier ones used > - sched_select_cpu() rewritten and it includes the check on current cpu's > idleness. > - cpu_idle() calls from timer and hrtimer removed now. > - Patch 2/3 from V1, removed as it doesn't apply to latest workqueue branch > from > tejun. > - CONFIG_MIGRATE_WQ removed and so is wq_select_cpu() > - sched_select_cpu() called only from __queue_work() > - got tejun/for-3.7 branch in my tree, before making workqueue changes. > > Viresh Kumar (3): > sched: Create sched_select_cpu() to give preferred CPU for power > saving > timer: hrtimer: Don't check idle_cpu() before calling > get_nohz_timer_target() > workqueue: Schedule work on non-idle cpu instead of current one
Hi Guys, I totally understand since last few weeks you guys were very busy as the merge window was around. So, didn't tried to disturb you then :) Can you please share your viewpoint on this patchset now? And also the running timer migration patch (which was sent separately)? Thanks in Advance. -- viresh _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
