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* sched: keep total / count stats in addition to the max forArjan van de Ven2008-01-251-0/+3
| | | | | | | | | | | | Right now, the linux kernel (with scheduler statistics enabled) keeps track of the maximum time a process is waiting to be scheduled. While the maximum is a very useful metric, tracking average and total is equally useful (at least for latencytop) to figure out the accumulated effect of scheduler delays. The accumulated effect is important to judge the performance impact of scheduler tuning/behavior. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix: don't take a mutex from interrupt contextPeter Zijlstra2008-01-251-2/+2
| | | | | | | | | print_cfs_stats is callable from interrupt context (sysrq), hence it should not take mutexes. Change it to use RCU since the task group data is RCU freed anyway. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: latencytop supportArjan van de Ven2008-01-251-1/+7
| | | | | | | | LatencyTOP kernel infrastructure; it measures latencies in the scheduler and tracks it system wide and per process. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: high-res preemption tickPeter Zijlstra2008-01-251-4/+65
| | | | | | | | | | | | | | | | Use HR-timers (when available) to deliver an accurate preemption tick. The regular scheduler tick that runs at 1/HZ can be too coarse when nice level are used. The fairness system will still keep the cpu utilisation 'fair' by then delaying the task that got an excessive amount of CPU time but try to minimize this by delivering preemption points spot-on. The average frequency of this extra interrupt is sched_latency / nr_latency. Which need not be higher than 1/HZ, its just that the distribution within the sched_latency period is important. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: RT-balance, add new methods to sched_classSteven Rostedt2008-01-251-0/+39
| | | | | | | | | | | | | | | | | Dmitry Adamushko found that the current implementation of the RT balancing code left out changes to the sched_setscheduler and rt_mutex_setprio. This patch addresses this issue by adding methods to the schedule classes to handle being switched out of (switched_from) and being switched into (switched_to) a sched_class. Also a method for changing of priorities is also added (prio_changed). This patch also removes some duplicate logic between rt_mutex_setprio and sched_setscheduler. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: remove do_div() from __sched_slice()Peter Zijlstra2008-01-251-1/+1
| | | | | | | | | | | Yanmin Zhang noticed a nice optimization: p = l * nr / nl, nl = l/g -> p = g * nr which eliminates a do_div() from __sched_period(). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: no need for 'affine wakeup' balancingDmitry Adamushko2008-01-251-0/+3
| | | | | | | | | | | No need to do a check for 'affine wakeup and passive balancing possibilities' in select_task_rq_fair() when task_cpu(p) == this_cpu. I guess, this part got missed upon introduction of per-sched_class select_task_rq() in try_to_wake_up(). Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: de-SCHED_OTHER-ize the RT pathGregory Haskins2008-01-251-0/+148
| | | | | | | | | | | | | | | | The current wake-up code path tries to determine if it can optimize the wake-up to "this_cpu" by computing load calculations. The problem is that these calculations are only relevant to SCHED_OTHER tasks where load is king. For RT tasks, priority is king. So the load calculation is completely wasted bandwidth. Therefore, we create a new sched_class interface to help with pre-wakeup routing decisions and move the load calculation as a function of CFS task's class. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: group scheduler, fix fairness of cpu bandwidth allocation for task groupsSrivatsa Vaddagiri2008-01-251-31/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current load balancing scheme isn't good enough for precise group fairness. For example: on a 8-cpu system, I created 3 groups as under: a = 8 tasks (cpu.shares = 1024) b = 4 tasks (cpu.shares = 1024) c = 3 tasks (cpu.shares = 1024) a, b and c are task groups that have equal weight. We would expect each of the groups to receive 33.33% of cpu bandwidth under a fair scheduler. This is what I get with the latest scheduler git tree: Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------------------- Col1 | Col2 | Col3 | Col4 ------|---------|-------|------------------------------------------------------- a | 277.676 | 57.8% | 54.1% 54.1% 54.1% 54.2% 56.7% 62.2% 62.8% 64.5% b | 116.108 | 24.2% | 47.4% 48.1% 48.7% 49.3% c | 86.326 | 18.0% | 47.5% 47.9% 48.5% -------------------------------------------------------------------------------- Explanation of o/p: Col1 -> Group name Col2 -> Cumulative execution time (in seconds) received by all tasks of that group in a 60sec window across 8 cpus Col3 -> CPU bandwidth received by the group in the 60sec window, expressed in percentage. Col3 data is derived as: Col3 = 100 * Col2 / (NR_CPUS * 60) Col4 -> CPU bandwidth received by each individual task of the group. Col4 = 100 * cpu_time_recd_by_task / 60 [I can share the test case that produces a similar o/p if reqd] The deviation from desired group fairness is as below: a = +24.47% b = -9.13% c = -15.33% which is quite high. After the patch below is applied, here are the results: -------------------------------------------------------------------------------- Col1 | Col2 | Col3 | Col4 ------|---------|-------|------------------------------------------------------- a | 163.112 | 34.0% | 33.2% 33.4% 33.5% 33.5% 33.7% 34.4% 34.8% 35.3% b | 156.220 | 32.5% | 63.3% 64.5% 66.1% 66.5% c | 160.653 | 33.5% | 85.8% 90.6% 91.4% -------------------------------------------------------------------------------- Deviation from desired group fairness is as below: a = +0.67% b = -0.83% c = +0.17% which is far better IMO. Most of other runs have yielded a deviation within +-2% at the most, which is good. Why do we see bad (group) fairness with current scheuler? ========================================================= Currently cpu's weight is just the summation of individual task weights. This can yield incorrect results. For ex: consider three groups as below on a 2-cpu system: CPU0 CPU1 --------------------------- A (10) B(5) C(5) --------------------------- Group A has 10 tasks, all on CPU0, Group B and C have 5 tasks each all of which are on CPU1. Each task has the same weight (NICE_0_LOAD = 1024). The current scheme would yield a cpu weight of 10240 (10*1024) for each cpu and the load balancer will think both CPUs are perfectly balanced and won't move around any tasks. This, however, would yield this bandwidth: A = 50% B = 25% C = 25% which is not the desired result. What's changing in the patch? ============================= - How cpu weights are calculated when CONFIF_FAIR_GROUP_SCHED is defined (see below) - API Change - Two tunables introduced in sysfs (under SCHED_DEBUG) to control the frequency at which the load balance monitor thread runs. The basic change made in this patch is how cpu weight (rq->load.weight) is calculated. Its now calculated as the summation of group weights on a cpu, rather than summation of task weights. Weight exerted by a group on a cpu is dependent on the shares allocated to it and also the number of tasks the group has on that cpu compared to the total number of (runnable) tasks the group has in the system. Let, W(K,i) = Weight of group K on cpu i T(K,i) = Task load present in group K's cfs_rq on cpu i T(K) = Total task load of group K across various cpus S(K) = Shares allocated to group K NRCPUS = Number of online cpus in the scheduler domain to which group K is assigned. Then, W(K,i) = S(K) * NRCPUS * T(K,i) / T(K) A load balance monitor thread is created at bootup, which periodically runs and adjusts group's weight on each cpu. To avoid its overhead, two min/max tunables are introduced (under SCHED_DEBUG) to control the rate at which it runs. Fixes from: Peter Zijlstra <a.p.zijlstra@chello.nl> - don't start the load_balance_monitor when there is only a single cpu. - rename the kthread because its currently longer than TASK_COMM_LEN Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: group scheduling, change how cpu load is calculatedSrivatsa Vaddagiri2008-01-251-4/+27
| | | | | | | | | | | | | | This patch changes how the cpu load exerted by fair_sched_class tasks is calculated. Load exerted by fair_sched_class tasks on a cpu is now a summation of the group weights, rather than summation of task weights. Weight exerted by a group on a cpu is dependent on the shares allocated to it. This version of patch has a minor impact on code size, but should have no runtime/functional impact for !CONFIG_FAIR_GROUP_SCHED. Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: group scheduling, minor fixesSrivatsa Vaddagiri2008-01-251-1/+3
| | | | | | | | | | | | | | Minor bug fixes for the group scheduler: - Use a mutex to serialize add/remove of task groups and also when changing shares of a task group. Use the same mutex when printing cfs_rq debugging stats for various task groups. - Use list_for_each_entry_rcu in for_each_leaf_cfs_rq macro (when walking task group list) Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: do not hurt SCHED_BATCH on wakeupIngo Molnar2007-12-181-2/+1
| | | | | | | | measurements by Yanmin Zhang have shown that SCHED_BATCH tasks benefit if they run the same place_entity() logic as SCHED_OTHER tasks - so uniformize behavior in this area. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: default to more agressive yield for SCHED_BATCH tasksIngo Molnar2007-12-041-3/+4
| | | | | | | | do more agressive yield for SCHED_BATCH tuned tasks: they are all about throughput anyway. This allows a gentler migration path for any apps that relied on stronger yield. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: cpu accounting controller (V2)Srivatsa Vaddagiri2007-12-021-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit cfb5285660aad4931b2ebbfa902ea48a37dfffa1 removed a useful feature for us, which provided a cpu accounting resource controller. This feature would be useful if someone wants to group tasks only for accounting purpose and doesnt really want to exercise any control over their cpu consumption. The patch below reintroduces the feature. It is based on Paul Menage's original patch (Commit 62d0df64065e7c135d0002f069444fbdfc64768f), with these differences: - Removed load average information. I felt it needs more thought (esp to deal with SMP and virtualized platforms) and can be added for 2.6.25 after more discussions. - Convert group cpu usage to be nanosecond accurate (as rest of the cfs stats are) and invoke cpuacct_charge() from the respective scheduler classes - Make accounting scalable on SMP systems by splitting the usage counter to be per-cpu - Move the code from kernel/cpu_acct.c to kernel/sched.c (since the code is not big enough to warrant a new file and also this rightly needs to live inside the scheduler. Also things like accessing rq->lock while reading cpu usage becomes easier if the code lived in kernel/sched.c) The patch also modifies the cpu controller not to provide the same accounting information. Tested-by: Balbir Singh <balbir@linux.vnet.ibm.com> Tested the patches on top of 2.6.24-rc3. The patches work fine. Ran some simple tests like cpuspin (spin on the cpu), ran several tasks in the same group and timed them. Compared their time stamps with cpuacct.usage. Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix minimum granularity tuningsZou Nan hai2007-11-261-6/+6
| | | | | | | | | | increase the default minimum granularity some more - this gives us more performance in aim7 benchmarks. also correct some comments: we scale with ilog(ncpus) + 1. Signed-off-by: Zou Nan hai <nanhai.zou@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: make sched_nr_latency staticAdrian Bunk2007-11-151-1/+1
| | | | | | | sched_nr_latency can now become static. Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix copy_namespace() <-> sched_fork() dependency in do_forkSrivatsa Vaddagiri2007-11-091-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Sukadev Bhattiprolu reported a kernel crash with control groups. There are couple of problems discovered by Suka's test: - The test requires the cgroup filesystem to be mounted with atleast the cpu and ns options (i.e both namespace and cpu controllers are active in the same hierarchy). # mkdir /dev/cpuctl # mount -t cgroup -ocpu,ns none cpuctl (or simply) # mount -t cgroup none cpuctl -> Will activate all controllers in same hierarchy. - The test invokes clone() with CLONE_NEWNS set. This causes a a new child to be created, also a new group (do_fork->copy_namespaces->ns_cgroup_clone-> cgroup_clone) and the child is attached to the new group (cgroup_clone-> attach_task->sched_move_task). At this point in time, the child's scheduler related fields are uninitialized (including its on_rq field, which it has inherited from parent). As a result sched_move_task thinks its on runqueue, when it isn't. As a solution to this problem, I moved sched_fork() call, which initializes scheduler related fields on a new task, before copy_namespaces(). I am not sure though whether moving up will cause other side-effects. Do you see any issue? - The second problem exposed by this test is that task_new_fair() assumes that parent and child will be part of the same group (which needn't be as this test shows). As a result, cfs_rq->curr can be NULL for the child. The solution is to test for curr pointer being NULL in task_new_fair(). With the patch below, I could run ns_exec() fine w/o a crash. Reported-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: clean up the wakeup preempt check, #2Ingo Molnar2007-11-091-3/+2
| | | | | | | | | | | clean up the preemption check to not use unnecessary 64-bit variables. This improves code size: text data bss dec hex filename 44227 3326 36 47589 b9e5 sched.o.before 44201 3326 36 47563 b9cb sched.o.after Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: clean up the wakeup preempt checkIngo Molnar2007-11-091-12/+13
| | | | | | | | | | clean up the wakeup preemption check. No code changed: text data bss dec hex filename 44227 3326 36 47589 b9e5 sched.o.before 44227 3326 36 47589 b9e5 sched.o.after Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: wakeup preemption fixIngo Molnar2007-11-091-4/+2
| | | | | | | | | wakeup preemption fix: do not make it dependent on p->prio. Preemption purely depends on ->vruntime. This improves preemption in mixed-nice-level workloads. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: remove PREEMPT_RESTRICTIngo Molnar2007-11-091-8/+2
| | | | | | | remove PREEMPT_RESTRICT. (this is a separate commit so that any regression related to the removal itself is bisectable) Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: reintroduce SMP tunings againIngo Molnar2007-11-091-9/+9
| | | | | | | | | | | | | | | | | | | Yanmin Zhang reported an aim7 regression and bisected it down to: | commit 38ad464d410dadceda1563f36bdb0be7fe4c8938 | Author: Ingo Molnar <mingo@elte.hu> | Date: Mon Oct 15 17:00:02 2007 +0200 | | sched: uniform tunings | | use the same defaults on both UP and SMP. fix this by reintroducing similar SMP tunings again. This resolves the regression. (also update the comments to match the ilog2(nr_cpus) tuning effect) Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: reintroduce the sched_min_granularity tunablePeter Zijlstra2007-11-091-7/+28
| | | | | | | | | | | | | | | we lost the sched_min_granularity tunable to a clever optimization that uses the sched_latency/min_granularity ratio - but the ratio is quite unintuitive to users and can also crash the kernel if the ratio is set to 0. So reintroduce the min_granularity tunable, while keeping the ratio maintained internally. no functionality changed. [ mingo@elte.hu: some fixlets. ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: documentation: place_entity() commentsPeter Zijlstra2007-11-091-2/+9
| | | | | | | Add a few comments to place_entity(). No code changed. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix vslicePeter Zijlstra2007-11-091-0/+1
| | | | | | | | | | | vslice was missing a factor NICE_0_LOAD, as weight is in weight*NICE_0_LOAD units. the effect of this bug was larger initial slices and thus latency-noisier forks. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix style of swap() macro in kernel/sched_fair.cIngo Molnar2007-10-291-1/+1
| | | | | | | | | fix style of swap() macro in kernel/sched_fair.c. ( this macro should eventually move to a general header, as ext3 uses a similar construct too. ) Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: isolate SMP balancing code a bit morePeter Williams2007-10-241-0/+4
| | | | | | | | | | | | | | | At the moment, a lot of load balancing code that is irrelevant to non SMP systems gets included during non SMP builds. This patch addresses this issue and reduces the binary size on non SMP systems: text data bss dec hex filename 10983 28 1192 12203 2fab sched.o.before 10739 28 1192 11959 2eb7 sched.o.after Signed-off-by: Peter Williams <pwil3058@bigpond.net.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: reduce balance-tasks overheadPeter Williams2007-10-241-11/+33
| | | | | | | | | | | | | | | At the moment, balance_tasks() provides low level functionality for both move_tasks() and move_one_task() (indirectly) via the load_balance() function (in the sched_class interface) which also provides dual functionality. This dual functionality complicates the interfaces and internal mechanisms and makes the run time overhead of operations that are called with two run queue locks held. This patch addresses this issue and reduces the overhead of these operations. Signed-off-by: Peter Williams <pwil3058@bigpond.net.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix new task startup crashSrivatsa Vaddagiri2007-10-171-5/+1
| | | | | | | | | | | | | | | Child task may be added on a different cpu that the one on which parent is running. In which case, task_new_fair() should check whether the new born task's parent entity should be added as well on the cfs_rq. Patch below fixes the problem in task_new_fair. This could fix the put_prev_task_fair() crashes reported. Reported-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Reported-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: reintroduce cache-hot affinityIngo Molnar2007-10-151-0/+2
| | | | | | | | reintroduce a simplified version of cache-hot/cold scheduling affinity. This improves performance with certain SMP workloads, such as sysbench. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: speed up context-switches a bitIngo Molnar2007-10-151-11/+0
| | | | | | | | | speed up context-switches a bit by not clearing p->exec_start. (as a side-effect, this also makes p->exec_start a universal timestamp available to cache-hot estimations.) Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: do not wakeup-preempt with SCHED_BATCH tasksIngo Molnar2007-10-151-0/+6
| | | | | | | do not wakeup-preempt with SCHED_BATCH tasks, their preemption is batched too, driven by the tick. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: update commentIngo Molnar2007-10-151-7/+5
| | | | | | update comment: clarify time-slices and remove obsolete tuning detail. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: prevent wakeup over-schedulingMike Galbraith2007-10-151-3/+11
| | | | | | | | | | | Prevent wakeup over-scheduling. Once a task has been preempted by a task of the same or lower priority, it becomes ineligible for repeated preemption by same until it has been ticked, or slept. Instead, the task is marked for preemption at the next tick. Tasks of higher priority still preempt immediately. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: disable forced preemption by defaultPeter Zijlstra2007-10-151-11/+13
| | | | | | | | Implement feature bit to disable forced preemption. This way it can be checked whether a workload is overscheduling or not. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix group scheduling for SCHED_BATCHDmitry Adamushko2007-10-151-3/+2
| | | | | | | | | The following patch (sched: disable sleeper_fairness on SCHED_BATCH) seems to break GROUP_SCHED. Although, it may be 'oops'-less due to the possibility of 'p' being always a valid address. Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: disable sleeper_fairness on SCHED_BATCHPeter Zijlstra2007-10-151-1/+3
| | | | | | | | disable sleeper fairness for batch tasks - they are about batch processing after all. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: another wakeup_granularity fixPeter Zijlstra2007-10-151-2/+5
| | | | | | | unit mis-match: wakeup_gran was used against a vruntime Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix: move the CPU check into ->task_new_fair()Ingo Molnar2007-10-151-1/+2
| | | | | | | | | | | | | noticed by Peter Zijlstra: fix: move the CPU check into ->task_new_fair(), this way we can call place_entity() and get child ->vruntime right at initial wakeup time. (without this there can be large latencies) Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
* sched: cleanup: function prototype cleanupsIngo Molnar2007-10-151-10/+5
| | | | | | | | | noticed by Thomas Gleixner: cleanup: function prototype cleanups - move into single line wherever possible. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: cleanup: rename SCHED_FEAT_USE_TREE_AVG to SCHED_FEAT_TREE_AVGIngo Molnar2007-10-151-1/+1
| | | | | | | cleanup: rename SCHED_FEAT_USE_TREE_AVG to SCHED_FEAT_TREE_AVG, to make SCHED_FEAT_ names more consistent. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: cleanup, make dequeue_entity() and update_stats_wait_end() similarDmitry Adamushko2007-10-151-4/+7
| | | | | | | | | | | | | | make dequeue_entity() / enqueue_entity() and update_stats_dequeue() / update_stats_enqueue() look similar, structure-wise. zero effect, functionality-wise: text data bss dec hex filename 34550 3026 100 37676 932c sched.o.before 34550 3026 100 37676 932c sched.o.after Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: cleanup, remove calc_weighted()Dmitry Adamushko2007-10-151-11/+0
| | | | | | | remove obsolete code -- calc_weighted() Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: uninline schedulerAlexey Dobriyan2007-10-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * save ~300 bytes * activate_idle_task() was moved to avoid a warning bloat-o-meter output: add/remove: 6/0 grow/shrink: 0/16 up/down: 438/-733 (-295) <=== function old new delta __enqueue_entity - 165 +165 finish_task_switch - 110 +110 update_curr_rt - 79 +79 __load_balance_iterator - 32 +32 __task_rq_unlock - 28 +28 find_process_by_pid - 24 +24 do_sched_setscheduler 133 123 -10 sys_sched_rr_get_interval 176 165 -11 sys_sched_getparam 156 145 -11 normalize_rt_tasks 482 470 -12 sched_getaffinity 112 99 -13 sys_sched_getscheduler 86 72 -14 sched_setaffinity 226 212 -14 sched_setscheduler 666 642 -24 load_balance_start_fair 33 9 -24 load_balance_next_fair 33 9 -24 dequeue_task_rt 133 67 -66 put_prev_task_rt 97 28 -69 schedule_tail 133 50 -83 schedule 682 594 -88 enqueue_entity 499 366 -133 task_new_fair 317 180 -137 Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: tweak wakeup granularityIngo Molnar2007-10-151-4/+4
| | | | | | tweak wakeup granularity. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix __pick_next_entity()Dmitry Adamushko2007-10-151-2/+5
| | | | | | | | | | | | | | | | | | | | | | | The thing is that __pick_next_entity() must never be called when first_fair(cfs_rq) == NULL. It wouldn't be a problem, should 'run_node' be the very first field of 'struct sched_entity' (and it's the second). The 'nr_running != 0' check is _not_ enough, due to the fact that 'current' is not within the tree. Generic paths are ok (e.g. schedule() as put_prev_task() is called previously)... I'm more worried about e.g. migration_call() -> CPU_DEAD_FROZEN -> migrate_dead_tasks()... if 'current' == rq->idle, no problems.. if it's one of the SCHED_NORMAL tasks (or imagine, some other use-cases in the future -- i.e. we should not make outer world dependent on internal details of sched_fair class) -- it may be "Houston, we've got a problem" case. it's +16 bytes to the ".text". Another variant is to make 'run_node' the first data member of 'struct sched_entity' but an additional check (se ! = NULL) is still needed in pick_next_entity(). Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
* sched: vslice fixups for non-0 nice levelsIngo Molnar2007-10-151-13/+40
| | | | | | | | | Make vslice accurate wrt nice levels, and add some comments while we're at it. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
* sched: mark scheduling classes as constIngo Molnar2007-10-151-3/+2
| | | | | | | | | | | | mark scheduling classes as const. The speeds up the code a bit and shrinks it: text data bss dec hex filename 40027 4018 292 44337 ad31 sched.o.before 40190 3842 292 44324 ad24 sched.o.after Signed-off-by: Ingo Molnar <mingo@elte.hu> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
* sched: group scheduler, fix latencySrivatsa Vaddagiri2007-10-151-0/+2
| | | | | | | | | | | | | | | There is a possibility that because of task of a group moving from one cpu to another, it may gain more cpu time that desired. See http://marc.info/?l=linux-kernel&m=119073197730334 for details. This is an attempt to fix that problem. Basically it simulates dequeue of higher level entities as if they are going to sleep. Similarly it simulate wakeup of higher level entities as if they are waking up from sleep. Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
* sched: group scheduler, fix bloatSrivatsa Vaddagiri2007-10-151-18/+25
| | | | | | | | | | | | | | Recent fix to check_preempt_wakeup() to check for preemption at higher levels caused a size bloat for !CONFIG_FAIR_GROUP_SCHED. Fix the problem. 42277 10598 320 53195 cfcb kernel/sched.o-before_this_patch 42216 10598 320 53134 cf8e kernel/sched.o-after_this_patch Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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