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* Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2009-09-11
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (64 commits) sched: Fix sched::sched_stat_wait tracepoint field sched: Disable NEW_FAIR_SLEEPERS for now sched: Keep kthreads at default priority sched: Re-tune the scheduler latency defaults to decrease worst-case latencies sched: Turn off child_runs_first sched: Ensure that a child can't gain time over it's parent after fork() sched: enable SD_WAKE_IDLE sched: Deal with low-load in wake_affine() sched: Remove short cut from select_task_rq_fair() sched: Turn on SD_BALANCE_NEWIDLE sched: Clean up topology.h sched: Fix dynamic power-balancing crash sched: Remove reciprocal for cpu_power sched: Try to deal with low capacity, fix update_sd_power_savings_stats() sched: Try to deal with low capacity sched: Scale down cpu_power due to RT tasks sched: Implement dynamic cpu_power sched: Add smt_gain sched: Update the cpu_power sum during load-balance sched: Add SD_PREFER_SIBLING ...
| * sched: Fix sched::sched_stat_wait tracepoint fieldIngo Molnar2009-09-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This weird perf trace output: cc1-9943 [001] 2802.059479616: sched_stat_wait: task: as:9944 wait: 2801938766276 [ns] Is caused by setting one component field of the delta to zero a bit too early. Move it to later. ( Note, this does not affect the NEW_FAIR_SLEEPERS interactivity bug, it's just a reporting bug in essence. ) Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nikos Chantziaras <realnc@arcor.de> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <4AA93D34.8040500@arcor.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Disable NEW_FAIR_SLEEPERS for nowIngo Molnar2009-09-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Nikos Chantziaras and Jens Axboe reported that turning off NEW_FAIR_SLEEPERS improves desktop interactivity visibly. Nikos described his experiences the following way: " With this setting, I can do "nice -n 19 make -j20" and still have a very smooth desktop and watch a movie at the same time. Various other annoyances (like the "logout/shutdown/restart" dialog of KDE not appearing at all until the background fade-out effect has finished) are also gone. So this seems to be the single most important setting that vastly improves desktop behavior, at least here. " Jens described it the following way, referring to a 10-seconds xmodmap scheduling delay he was trying to debug: " Then I tried switching NO_NEW_FAIR_SLEEPERS on, and then I get: Performance counter stats for 'xmodmap .xmodmap-carl': 9.009137 task-clock-msecs # 0.447 CPUs 18 context-switches # 0.002 M/sec 1 CPU-migrations # 0.000 M/sec 315 page-faults # 0.035 M/sec 0.020167093 seconds time elapsed Woot! " So disable it for now. In perf trace output i can see weird delta timestamps: cc1-9943 [001] 2802.059479616: sched_stat_wait: task: as:9944 wait: 2801938766276 [ns] That nsec field is not supposed to be that large. More digging is needed - but lets turn it off while the real bug is found. Reported-by: Nikos Chantziaras <realnc@arcor.de> Tested-by: Nikos Chantziaras <realnc@arcor.de> Reported-by: Jens Axboe <jens.axboe@oracle.com> Tested-by: Jens Axboe <jens.axboe@oracle.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <4AA93D34.8040500@arcor.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Keep kthreads at default priorityMike Galbraith2009-09-09
| | | | | | | | | | | | | | | | | | | | Removes kthread/workqueue priority boost, they increase worst-case desktop latencies. Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1252486344.28645.18.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Re-tune the scheduler latency defaults to decrease worst-case latenciesMike Galbraith2009-09-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reduce the latency target from 20 msecs to 5 msecs. Why? Larger latencies increase spread, which is good for scaling, but bad for worst case latency. We still have the ilog(nr_cpus) rule to scale up on bigger server boxes. Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1252486344.28645.18.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Turn off child_runs_firstMike Galbraith2009-09-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Set child_runs_first default to off. It hurts 'optimal' make -j<NR_CPUS> workloads as make jobs get preempted by child tasks, reducing parallelism. Note, this patch might make existing races in user applications more prominent than before - so breakages might be bisected to this commit. Child-runs-first is broken on SMP to begin with, and we already had it off briefly in v2.6.23 so most of the offenders ought to be fixed. Would be nice not to revert this commit but fix those apps finally ... Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1252486344.28645.18.camel@marge.simson.net> [ made the sysctl independent of CONFIG_SCHED_DEBUG, in case people want to work around broken apps. ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Ensure that a child can't gain time over it's parent after fork()Mike Galbraith2009-09-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A fork/exec load is usually "pass the baton", so the child should never be placed behind the parent. With START_DEBIT we make room for the new task, but with child_runs_first, that room comes out of the _parent's_ hide. There's nothing to say that the parent wasn't ahead of min_vruntime at fork() time, which means that the "baton carrier", who is essentially the parent in drag, can gain time and increase scheduling latencies for waiters. With NEW_FAIR_SLEEPERS + START_DEBIT + child_runs_first enabled, we essentially pass the sleeper fairness off to the child, which is fine, but if we don't base placement on the parent's updated vruntime, we can end up compounding latency woes if the child itself then does fork/exec. The debit incurred at fork doesn't hurt the parent who is then going to sleep and maybe exit, but the child who acquires the error harms all comers. This improves latencies of make -j<n> kernel build workloads. Reported-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: enable SD_WAKE_IDLEPeter Zijlstra2009-09-07
| | | | | | | | | | | | | | | | | | Now that SD_WAKE_IDLE doesn't make pipe-test suck anymore, enable it by default for MC, CPU and NUMA domains. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Deal with low-load in wake_affine()Peter Zijlstra2009-09-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | wake_affine() would always fail under low-load situations where both prev and this were idle, because adding a single task will always be a significant imbalance, even if there's nothing around that could balance it. Deal with this by allowing imbalance when there's nothing you can do about it. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Remove short cut from select_task_rq_fair()Peter Zijlstra2009-09-07
| | | | | | | | | | | | | | | | | | | | | | | | | | select_task_rq_fair() incorrectly skips the wake_affine() logic, remove this. When prev_cpu == this_cpu, the code jumps straight to the wake_idle() logic, this doesn't give the wake_affine() logic the chance to pin the task to this cpu. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Turn on SD_BALANCE_NEWIDLEIngo Molnar2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Start the re-tuning of the balancer by turning on newidle. It improves hackbench performance and parallelism on a 4x4 box. The "perf stat --repeat 10" measurements give us: domain0 domain1 ....................................... -SD_BALANCE_NEWIDLE -SD_BALANCE_NEWIDLE: 2041.273208 task-clock-msecs # 9.354 CPUs ( +- 0.363% ) +SD_BALANCE_NEWIDLE -SD_BALANCE_NEWIDLE: 2086.326925 task-clock-msecs # 11.934 CPUs ( +- 0.301% ) +SD_BALANCE_NEWIDLE +SD_BALANCE_NEWIDLE: 2115.289791 task-clock-msecs # 12.158 CPUs ( +- 0.263% ) Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Clean up topology.hIngo Molnar2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Re-organize the flag settings so that it's visible at a glance which sched-domains flags are set and which not. With the new balancer code we'll need to re-tune these details anyway, so make it cleaner to make fewer mistakes down the road ;-) Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Fix dynamic power-balancing crashIngo Molnar2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This crash: [ 1774.088275] divide error: 0000 [#1] SMP [ 1774.100355] CPU 13 [ 1774.102498] Modules linked in: [ 1774.105631] Pid: 30881, comm: hackbench Not tainted 2.6.31-rc8-tip-01308-g484d664-dirty #1629 X8DTN [ 1774.114807] RIP: 0010:[<ffffffff81041c38>] [<ffffffff81041c38>] sched_balance_self+0x19b/0x2d4 Triggers because update_group_power() modifies the sd tree and does temporary calculations there - not considering that other CPUs could observe intermediate values, such as the zero initial value. Calculate it in a temporary variable instead. (we need no memory barrier as these are all statistical values anyway) Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20090904092742.GA11014@elte.hu> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Remove reciprocal for cpu_powerPeter Zijlstra2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Its a source of fail, also, now that cpu_power is dynamical, its a waste of time. before: <idle>-0 [000] 132.877936: find_busiest_group: avg_load: 0 group_load: 8241 power: 1 after: bash-1689 [001] 137.862151: find_busiest_group: avg_load: 10636288 group_load: 10387 power: 1 [ v2: build fix from From: Andreas Herrmann ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083826.425896304@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Try to deal with low capacity, fix update_sd_power_savings_stats()Gautham R Shenoy2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sgs.group_capacity can now be 0, if for some reason group->__cpu_power happens to be less than SCHED_LOAD_SCALE/2. In that case, we need the following fix to make it work for update_sd_power_savings_stats(). That's because both sum_nr_running and group_capacity are unsigned longs. Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Try to deal with low capacityPeter Zijlstra2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When the capacity drops low, we want to migrate load away. Allow the load-balancer to remove all tasks when we hit rock bottom. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083826.342231003@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Scale down cpu_power due to RT tasksPeter Zijlstra2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | Keep an average on the amount of time spend on RT tasks and use that fraction to scale down the cpu_power for regular tasks. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083826.287778431@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Implement dynamic cpu_powerPeter Zijlstra2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | Recompute the cpu_power for each cpu during load-balance. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083826.162033479@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Add smt_gainPeter Zijlstra2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The idea is that multi-threading a core yields more work capacity than a single thread, provide a way to express a static gain for threads. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083826.073345955@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Update the cpu_power sum during load-balancePeter Zijlstra2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | In order to prepare for a more dynamic cpu_power, update the group sum while walking the sched domains during load-balance. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083825.985050292@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Add SD_PREFER_SIBLINGPeter Zijlstra2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | Do the placement thing using SD flags. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083825.897028974@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Restore __cpu_power to a straight sum of powerPeter Zijlstra2009-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cpu_power is supposed to be a representation of the process capacity of the cpu, not a value to randomly tweak in order to affect placement. Remove the placement hacks. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083825.810860576@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| *-. Merge branches 'sched/domains' and 'sched/clock' into sched/coreIngo Molnar2009-09-04
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | Merge reason: both topics are ready now, and we want to merge dependent changes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | * init: Move sched_clock_init after late_time_initThomas Gleixner2009-08-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some architectures initialize clocks and timers in late_time_init and x86 wants to do the same to avoid FIXMAP hackery for calibrating the TSC. That would result in undefined sched_clock readout and wreckaged printk timestamps again. We probably have those already on archs which do all their time/clock setup in late_time_init. There is no harm to move that after late_time_init except that a few more boot timestamps are stale. The scheduler is not active at that point so no real wreckage is expected. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: linux-arch@vger.kernel.org
| | * | sched: Consolidate definition of variable sd in __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818110229.GM29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Separate out build of NUMA sched groups from __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... to further strip down __build_sched_domains(). Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818110111.GL29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Separate out build of ALLNODES sched groups from __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For the sake of completeness. Now all calls to init_sched_build_groups() are contained in build_sched_groups(). Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818110013.GK29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Separate out build of CPU sched groups from __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... to further strip down __build_sched_domains(). Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818105928.GJ29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Separate out build of MC sched groups from __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... to further strip down __build_sched_domains(). Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818105838.GI29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Separate out build of SMT sched groups from __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... to further strip down __build_sched_domains(). Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818105751.GH29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Separate out build of SMT sched domain from __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... to further strip down __build_sched_domains(). Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818105703.GG29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Separate out build of MC sched domain from __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... to further strip down __build_sched_domains(). Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818105614.GF29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Separate out build of CPU sched domain from __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... to further strip down __build_sched_domains(). Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818105455.GE29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Separate out build of NUMA sched domain from __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... to further strip down __build_sched_domains(). Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818105406.GD29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Separate out allocation/free/goto-hell from __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818105300.GC29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Use structure to store local data in __build_sched_domainsAndreas Herrmann2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090818105152.GB29515@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | sched: Add wait, sleep and iowait accounting tracepointsPeter Zijlstra2009-09-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add 3 schedstat tracepoints to help account for wait-time, sleep-time and iowait-time. They can also be used as a perf-counter source to profile tasks on these clocks. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arjan van de Ven <arjan@linux.intel.com> LKML-Reference: <new-submission> [ build fix for the !CONFIG_SCHEDSTATS case ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | sched: Provide iowait countersArjan van de Ven2009-09-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For counting how long an application has been waiting for (disk) IO, there currently is only the HZ sample driven information available, while for all other counters in this class, a high resolution version is available via CONFIG_SCHEDSTATS. In order to make an improved bootchart tool possible, we also need a higher resolution version of the iowait time. This patch below adds this scheduler statistic to the kernel. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4A64B813.1080506@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | Merge commit 'v2.6.31-rc8' into sched/coreIngo Molnar2009-09-02
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge reason: bump from rc5 to rc8, but also pick up TP_perf_assign() API, a patch will be queued that depends on it. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | sched: Rename init_cfs_rq => init_tg_cfs_rqAnirban Sinha2009-08-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... so that it does not share a common name with a function within the same scope. Signed-off-by: Anirban Sinha <asinha@zeugmasystems.com> LKML-Reference: <DDFD17CC94A9BD49A82147DDF7D545C501EA98A6@exchange.ZeugmaSystems.local> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | sched: Fix division by zero - reallyPeter Zijlstra2009-08-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When re-computing the shares for each task group's cpu representation we need the ratio of weight on each cpu vs the total weight of the sched domain. Since load-balancing is loosely (read not) synchronized, the weight of individual cpus can change between doing the sum and calculating the ratio. The previous patch dealt with only one of the race scenarios, this patch side steps them all by saving a snapshot of all the individual cpu weights, thereby always working on a consistent set. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: torvalds@linux-foundation.org Cc: jes@sgi.com Cc: jens.axboe@oracle.com Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <1251371336.18584.77.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | sched: Avoid division by zeroPeter Zijlstra2009-08-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch a5004278f0525dcb9aa43703ef77bf371ea837cd (sched: Fix cgroup smp fairness) introduced the possibility of a divide-by-zero because load-balancing is not synchronized between sched_domains. This can cause the state of cpus to change between the first and second loop over the sched domain in tg_shares_up(). Reported-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Jes Sorensen <jes@sgi.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <1250855934.7538.30.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | sched: Use for_each_class macro in move_one_task()Hiroshi Shimamoto2009-08-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace for loop with the macro for_each_class to cleanup. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> LKML-Reference: <4A8A277D.4090304@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | sched, task_struct: stack_canary is not needed without CC_STACKPROTECTORHiroshi Shimamoto2009-08-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The field stack_canary is only used with CC_STACKPROTECTOR. This patch reduces task_struct size without CC_STACKPROTECTOR. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> LKML-Reference: <4A8A44CA.2020701@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | sched: Add default defines for PREEMPT_ACTIVEArnd Bergmann2009-08-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The PREEMPT_ACTIVE setting doesn't actually need to be arch-specific, so set up a sane default for all arches to (hopefully) migrate to. > if we look at linux/hardirq.h, it makes this claim: > * - bit 28 is the PREEMPT_ACTIVE flag > if that's true, then why are we letting any arch set this define ? a > quick survey shows that half the arches (11) are using 0x10000000 (bit > 28) while the other half (10) are using 0x4000000 (bit 26). and then > there is the ia64 oddity which uses bit 30. the exact value here > shouldnt really matter across arches though should it ? actually alpha, arm and avr32 also use bit 30 (0x40000000), there are only five (or eight, depending on how you count) architectures (blackfin, h8300, m68k, s390 and sparc) using bit 26. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | sched: Fix cpupri build on !CONFIG_SMPIngo Molnar2009-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This build bug: In file included from kernel/sched.c:1765: kernel/sched_rt.c: In function ‘has_pushable_tasks’: kernel/sched_rt.c:1069: error: ‘struct rt_rq’ has no member named ‘pushable_tasks’ kernel/sched_rt.c: In function ‘pick_next_task_rt’: kernel/sched_rt.c:1084: error: ‘struct rq’ has no member named ‘post_schedule’ Triggers because both pushable_tasks and post_schedule are SMP-only fields. Move pushable_tasks() to the SMP section and #ifdef the post_schedule use. Cc: Gregory Haskins <ghaskins@novell.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090729150422.17691.55590.stgit@dev.haskins.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | sched: Ensure the migration task doesn't go away during usePeter Zijlstra2009-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Like sched_migrate_task(), set_cpus_allowed_ptr() should hold onto the migration thread too. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | sched: Add debug check to task_of()Peter Zijlstra2009-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A frequent mistake appears to be to call task_of() on a scheduler entity that is not actually a task, which can result in a wild pointer. Add a check to catch these mistakes. Suggested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | sched: Fully integrate cpus_active_map and root-domain codeGregory Haskins2009-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reflect "active" cpus in the rq->rd->online field, instead of the online_map. The motivation is that things that use the root-domain code (such as cpupri) only care about cpus classified as "active" anyway. By synchronizing the root-domain state with the active map, we allow several optimizations. For instance, we can remove an extra cpumask_and from the scheduler hotpath by utilizing rq->rd->online (since it is now a cached version of cpu_active_map & rq->rd->span). Signed-off-by: Gregory Haskins <ghaskins@novell.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Max Krasnyansky <maxk@qualcomm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090730145723.25226.24493.stgit@dev.haskins.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | sched: Enhance the pre/post scheduling logicGregory Haskins2009-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We currently have an explicit "needs_post" vtable method which returns a stack variable for whether we should later run post-schedule. This leads to an awkward exchange of the variable as it bubbles back up out of the context switch. Peter Zijlstra observed that this information could be stored in the run-queue itself instead of handled on the stack. Therefore, we revert to the method of having context_switch return void, and update an internal rq->post_schedule variable when we require further processing. In addition, we fix a race condition where we try to access current->sched_class without holding the rq->lock. This is technically racy, as the sched-class could change out from under us. Instead, we reference the per-rq post_schedule variable with the runqueue unlocked, but with preemption disabled to see if we need to reacquire the rq->lock. Finally, we clean the code up slightly by removing the #ifdef CONFIG_SMP conditionals from the schedule() call, and implement some inline helper functions instead. This patch passes checkpatch, and rt-migrate. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090729150422.17691.55590.stgit@dev.haskins.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>