Integration of cpuidle with the scheduler requires that the idle loop be
closely integrated with the scheduler proper. Moving cpu/idle.c into the
sched directory will allow for a smoother integration, and eliminate a
subdirectory which contained only one source file.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.LFD.2.11.1401301102210.1652@knanqh.ubzr
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tracking rq->max_idle_balance_cost and sd->max_newidle_lb_cost.
It's useful to know these values in debug mode.
Signed-off-by: Alex Shi <alex.shi@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/52E0F3BF.5020904@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since is_same_group() is only used in the group scheduling code, there is
no need to define it outside CONFIG_FAIR_GROUP_SCHED.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1391005773-29493-1-git-send-email-dietmar.eggemann@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch both merged idle_balance() and pre_schedule() and pushes
both of them into pick_next_task().
Conceptually pre_schedule() and idle_balance() are rather similar,
both are used to pull more work onto the current CPU.
We cannot however first move idle_balance() into pre_schedule_fair()
since there is no guarantee the last runnable task is a fair task, and
thus we would miss newidle balances.
Similarly, the dl and rt pre_schedule calls must be ran before
idle_balance() since their respective tasks have higher priority and
it would not do to delay their execution searching for less important
tasks first.
However, by noticing that pick_next_tasks() already traverses the
sched_class hierarchy in the right order, we can get the right
behaviour and do away with both calls.
We must however change the special case optimization to also require
that prev is of sched_class_fair, otherwise we can miss doing a dl or
rt pull where we needed one.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/n/tip-a8k6vvaebtn64nie345kx1je@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The idle post_schedule flag is just a vile waste of time, furthermore
it appears unneeded, move the idle_enter_fair() call into
pick_next_task_idle().
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: alex.shi@linaro.org
Cc: mingo@kernel.org
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-aljykihtxJt3mkokxi0qZurb@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since commit 2f36825b1 ("sched: Next buddy hint on sleep and preempt
path") it is likely we pick a new task from the same cgroup, doing a put
and then set on all intermediate entities is a waste of time, so try to
avoid this.
Measured using:
mount nodev /cgroup -t cgroup -o cpu
cd /cgroup
mkdir a; cd a
mkdir b; cd b
mkdir c; cd c
echo $$ > tasks
perf stat --repeat 10 -- taskset 1 perf bench sched pipe
PRE : 4.542422684 seconds time elapsed ( +- 0.33% )
POST: 4.389409991 seconds time elapsed ( +- 0.32% )
Which shows a significant improvement of ~3.5%
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1328936700.2476.17.camel@laptop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In order to avoid having to do put/set on a whole cgroup hierarchy
when we context switch, push the put into pick_next_task() so that
both operations are in the same function. Further changes then allow
us to possibly optimize away redundant work.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1328936700.2476.17.camel@laptop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Track depth in cgroup tree, this is useful for things like
find_matching_se() where you need to get to a common parent of two
sched entities.
Keeping the depth avoids having to calculate it on the spot, which
saves a number of possible cache-misses.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1328936700.2476.17.camel@laptop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
idle_balance() modifies the rq->idle_stamp field, making this information
shared across core.c and fair.c.
As we know if the cpu is going to idle or not with the previous patch, let's
encapsulate the rq->idle_stamp information in core.c by moving it up to the
caller.
The idle_balance() function returns true in case a balancing occured and the
cpu won't be idle, false if no balance happened and the cpu is going idle.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: alex.shi@linaro.org
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1389949444-14821-3-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The scheduler main function 'schedule()' checks if there are no more tasks
on the runqueue. Then it checks if a task should be pulled in the current
runqueue in idle_balance() assuming it will go to idle otherwise.
But idle_balance() releases the rq->lock in order to look up the sched
domains and takes the lock again right after. That opens a window where
another cpu may put a task in our runqueue, so we won't go to idle but
we have filled the idle_stamp, thinking we will.
This patch closes the window by checking if the runqueue has been modified
but without pulling a task after taking the lock again, so we won't go to idle
right after in the __schedule() function.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: alex.shi@linaro.org
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1389949444-14821-2-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
As patch "sched: Move the priority specific bits into a new header file" exposes
the priority related macros in linux/sched/prio.h, we don't have to implement
task_nice() in kernel/sched/core.c any more.
This patch implements it in linux/sched/sched.h as static inline function,
saving the kernel stack and enhancing performance a bit.
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Cc: clark.williams@gmail.com
Cc: rostedt@goodmis.org
Cc: raistlin@linux.it
Cc: juri.lelli@gmail.com
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1390878045-7096-1-git-send-email-yangds.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When p is current and it's not of dl class, then there are no other
dl taks in the rq. If we had had pushable tasks in some other rq,
they would have been pushed earlier. So, skip "p == rq->curr" case.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Acked-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140128072421.32315.25300.stgit@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull timer/dynticks updates from Ingo Molnar:
"This tree contains misc dynticks updates: a fix and three cleanups"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/nohz: Fix overflow error in scheduler_tick_max_deferment()
nohz_full: fix code style issue of tick_nohz_full_stop_tick
nohz: Get timekeeping max deferment outside jiffies_lock
tick: Rename tick_check_idle() to tick_irq_enter()
Cleanup suggested by Mel Gorman. Now the code contains some more
hints on what statistics go where.
Suggested-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Link: http://lkml.kernel.org/r/1390860228-21539-10-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We track both the node of the memory after a NUMA fault, and the node
of the CPU on which the fault happened. Rename the local variables in
task_numa_fault to make things more explicit.
Suggested-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Link: http://lkml.kernel.org/r/1390860228-21539-9-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The current code in task_numa_placement calculates the difference
between the old and the new value, but also temporarily stores half
of the old value in the per-process variables.
The NUMA balancing code looks at those per-process variables, and
having other tasks temporarily see halved statistics could lead to
unwanted numa migrations. This can be avoided by doing all the math
in local variables.
This change also simplifies the code a little.
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Link: http://lkml.kernel.org/r/1390860228-21539-8-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tracing the code that decides the active nodes has made it abundantly clear
that the naive implementation of the faults_from code has issues.
Specifically, the garbage collector in some workloads will access orders
of magnitudes more memory than the threads that do all the active work.
This resulted in the node with the garbage collector being marked the only
active node in the group.
This issue is avoided if we weigh the statistics by CPU use of each task in
the numa group, instead of by how many faults each thread has occurred.
To achieve this, we normalize the number of faults to the fraction of faults
that occurred on each node, and then multiply that fraction by the fraction
of CPU time the task has used since the last time task_numa_placement was
invoked.
This way the nodes in the active node mask will be the ones where the tasks
from the numa group are most actively running, and the influence of eg. the
garbage collector and other do-little threads is properly minimized.
On a 4 node system, using CPU use statistics calculated over a longer interval
results in about 1% fewer page migrations with two 32-warehouse specjbb runs
on a 4 node system, and about 5% fewer page migrations, as well as 1% better
throughput, with two 8-warehouse specjbb runs, as compared with the shorter
term statistics kept by the scheduler.
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Link: http://lkml.kernel.org/r/1390860228-21539-7-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Use the active_nodes nodemask to make smarter decisions on NUMA migrations.
In order to maximize performance of workloads that do not fit in one NUMA
node, we want to satisfy the following criteria:
1) keep private memory local to each thread
2) avoid excessive NUMA migration of pages
3) distribute shared memory across the active nodes, to
maximize memory bandwidth available to the workload
This patch accomplishes that by implementing the following policy for
NUMA migrations:
1) always migrate on a private fault
2) never migrate to a node that is not in the set of active nodes
for the numa_group
3) always migrate from a node outside of the set of active nodes,
to a node that is in that set
4) within the set of active nodes in the numa_group, only migrate
from a node with more NUMA page faults, to a node with fewer
NUMA page faults, with a 25% margin to avoid ping-ponging
This results in most pages of a workload ending up on the actively
used nodes, with reduced ping-ponging of pages between those nodes.
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Link: http://lkml.kernel.org/r/1390860228-21539-6-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The numa_faults_cpu statistics are used to maintain an active_nodes nodemask
per numa_group. This allows us to be smarter about when to do numa migrations.
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Link: http://lkml.kernel.org/r/1390860228-21539-5-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Track which nodes NUMA faults are triggered from, in other words
the CPUs on which the NUMA faults happened. This uses a similar
mechanism to what is used to track the memory involved in numa faults.
The next patches use this to build up a bitmap of which nodes a
workload is actively running on.
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Link: http://lkml.kernel.org/r/1390860228-21539-4-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In order to get a more consistent naming scheme, making it clear
which fault statistics track memory locality, and which track
CPU locality, rename the memory fault statistics.
Suggested-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Link: http://lkml.kernel.org/r/1390860228-21539-3-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Excessive migration of pages can hurt the performance of workloads
that span multiple NUMA nodes. However, it turns out that the
p->numa_migrate_deferred knob is a really big hammer, which does
reduce migration rates, but does not actually help performance.
Now that the second stage of the automatic numa balancing code
has stabilized, it is time to replace the simplistic migration
deferral code with something smarter.
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Link: http://lkml.kernel.org/r/1390860228-21539-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Not all classes implement (or can implement) a useful get_rr_interval()
function, default to a 0 time-slice for them.
This fixes a crash reported by Tommi Rantala.
Reported-by: Tommi Rantala <tt.rantala@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Tommi Rantala <tt.rantala@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140127105413.GC11314@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add in Documentation/scheduler/ some hints about the design
choices, the usage and the future possible developments of the
sched_dl scheduling class and of the SCHED_DEADLINE policy.
Reviewed-by: Henrik Austad <henrik@austad.us>
Signed-off-by: Dario Faggioli <raistlin@linux.it>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
[ Re-wrote sections 2 and 3. ]
Signed-off-by: Luca Abeni <luca.abeni@unitn.it>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1390821615-23247-1-git-send-email-juri.lelli@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull scheduler fixes from Ingo Molnar:
"A couple of regression fixes mostly hitting virtualized setups, but
also some bare metal systems"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/x86/tsc: Initialize multiplier to 0
sched/clock: Fixup early initialization
sched/preempt/x86: Fix voluntary preempt for x86
Revert "sched: Fix sleep time double accounting in enqueue entity"
Add a working sysctl to enable/disable automatic numa memory balancing
at runtime.
This allows us to track down performance problems with this feature and
is generally a good idea.
This was possible earlier through debugfs, but only with special
debugging options set. Also fix the boot message.
[akpm@linux-foundation.org: s/sched_numa_balancing/sysctl_numa_balancing/]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The code would assume sched_clock_stable() and switch to !stable
later, this switch brings a discontinuity in time.
The discontinuity on switching from stable to unstable was always
present, but previously we would set stable/unstable before
initializing TSC and usually stick to the one we start out with.
So the static_key bits brought an extra switch where there previously
wasn't one.
Things are further complicated by the fact that we cannot use
static_key as early as we usually call set_sched_clock_stable().
Fix things by tracking the stable state in a regular variable and only
set the static_key to the right state on sched_clock_init(), which is
ran right after late_time_init->tsc_init().
Before this we would not be using the TSC anyway.
Reported-and-Tested-by: Sasha Levin <sasha.levin@oracle.com>
Reported-by: dyoung@redhat.com
Fixes: 35af99e646 ("sched/clock, x86: Use a static_key for sched_clock_stable")
Cc: jacob.jun.pan@linux.intel.com
Cc: Mike Galbraith <bitbucket@online.de>
Cc: hpa@zytor.com
Cc: paulmck@linux.vnet.ibm.com
Cc: John Stultz <john.stultz@linaro.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: lenb@kernel.org
Cc: rjw@rjwysocki.net
Cc: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Cc: rui.zhang@intel.com
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140122115918.GG3694@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This reverts commit 282cf499f0.
With the current implementation, the load average statistics of a sched entity
change according to other activity on the CPU even if this activity is done
between the running window of the sched entity and have no influence on the
running duration of the task.
When a task wakes up on the same CPU, we currently update last_runnable_update
with the return of __synchronize_entity_decay without updating the
runnable_avg_sum and runnable_avg_period accordingly. In fact, we have to sync
the load_contrib of the se with the rq's blocked_load_contrib before removing
it from the latter (with __synchronize_entity_decay) but we must keep
last_runnable_update unchanged for updating runnable_avg_sum/period during the
next update_entity_load_avg.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Cc: pjt@google.com
Cc: alex.shi@linaro.org
Link: http://lkml.kernel.org/r/1390376734-6800-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Merge first patch-bomb from Andrew Morton:
- a couple of misc things
- inotify/fsnotify work from Jan
- ocfs2 updates (partial)
- about half of MM
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (117 commits)
mm/migrate: remove unused function, fail_migrate_page()
mm/migrate: remove putback_lru_pages, fix comment on putback_movable_pages
mm/migrate: correct failure handling if !hugepage_migration_support()
mm/migrate: add comment about permanent failure path
mm, page_alloc: warn for non-blockable __GFP_NOFAIL allocation failure
mm: compaction: reset scanner positions immediately when they meet
mm: compaction: do not mark unmovable pageblocks as skipped in async compaction
mm: compaction: detect when scanners meet in isolate_freepages
mm: compaction: reset cached scanner pfn's before reading them
mm: compaction: encapsulate defer reset logic
mm: compaction: trace compaction begin and end
memcg, oom: lock mem_cgroup_print_oom_info
sched: add tracepoints related to NUMA task migration
mm: numa: do not automatically migrate KSM pages
mm: numa: trace tasks that fail migration due to rate limiting
mm: numa: limit scope of lock for NUMA migrate rate limiting
mm: numa: make NUMA-migrate related functions static
lib/show_mem.c: show num_poisoned_pages when oom
mm/hwpoison: add '#' to hwpoison_inject
mm/memblock: use WARN_ONCE when MAX_NUMNODES passed as input parameter
...
Pull cgroup updates from Tejun Heo:
"The bulk of changes are cleanups and preparations for the upcoming
kernfs conversion.
- cgroup_event mechanism which is and will be used only by memcg is
moved to memcg.
- pidlist handling is updated so that it can be served by seq_file.
Also, the list is not sorted if sane_behavior. cgroup
documentation explicitly states that the file is not sorted but it
has been for quite some time.
- All cgroup file handling now happens on top of seq_file. This is
to prepare for kernfs conversion. In addition, all operations are
restructured so that they map 1-1 to kernfs operations.
- Other cleanups and low-pri fixes"
* 'for-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (40 commits)
cgroup: trivial style updates
cgroup: remove stray references to css_id
doc: cgroups: Fix typo in doc/cgroups
cgroup: fix fail path in cgroup_load_subsys()
cgroup: fix missing unlock on error in cgroup_load_subsys()
cgroup: remove for_each_root_subsys()
cgroup: implement for_each_css()
cgroup: factor out cgroup_subsys_state creation into create_css()
cgroup: combine css handling loops in cgroup_create()
cgroup: reorder operations in cgroup_create()
cgroup: make for_each_subsys() useable under cgroup_root_mutex
cgroup: css iterations and css_from_dir() are safe under cgroup_mutex
cgroup: unify pidlist and other file handling
cgroup: replace cftype->read_seq_string() with cftype->seq_show()
cgroup: attach cgroup_open_file to all cgroup files
cgroup: generalize cgroup_pidlist_open_file
cgroup: unify read path so that seq_file is always used
cgroup: unify cgroup_write_X64() and cgroup_write_string()
cgroup: remove cftype->read(), ->read_map() and ->write()
hugetlb_cgroup: convert away from cftype->read()
...
This patch adds three tracepoints
o trace_sched_move_numa when a task is moved to a node
o trace_sched_swap_numa when a task is swapped with another task
o trace_sched_stick_numa when a numa-related migration fails
The tracepoints allow the NUMA scheduler activity to be monitored and the
following high-level metrics can be calculated
o NUMA migrated stuck nr trace_sched_stick_numa
o NUMA migrated idle nr trace_sched_move_numa
o NUMA migrated swapped nr trace_sched_swap_numa
o NUMA local swapped trace_sched_swap_numa src_nid == dst_nid (should never happen)
o NUMA remote swapped trace_sched_swap_numa src_nid != dst_nid (should == NUMA migrated swapped)
o NUMA group swapped trace_sched_swap_numa src_ngid == dst_ngid
Maybe a small number of these are acceptable
but a high number would be a major surprise.
It would be even worse if bounces are frequent.
o NUMA avg task migs. Average number of migrations for tasks
o NUMA stddev task mig Self-explanatory
o NUMA max task migs. Maximum number of migrations for a single task
In general the intent of the tracepoints is to help diagnose problems
where automatic NUMA balancing appears to be doing an excessive amount
of useless work.
[akpm@linux-foundation.org: remove semicolon-after-if, repair coding-style]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With the introduction of sched_attr::sched_nice we need to check
if we've got permission to actually change the nice value.
Daniel found that can_nice() would always fail; and upon
inspection it turns out that can_nice() only tests to see if we
can lower the nice value, but it doesn't validate if we're
lowering or not.
Therefore amend the test to only call can_nice() when we lower
the nice value.
Reported-and-Tested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: raistlin@linux.it
Cc: juri.lelli@gmail.com
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Fixes: d50dde5a10 ("sched: Add new scheduler syscalls to support an extended scheduling parameters ABI")
Link: http://lkml.kernel.org/r/20140116165425.GA9481@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
I noticed the new sched_{set,get}attr() calls didn't properly deal
with the SCHED_RESET_ON_FORK hack.
Instead of propagating the flags in high bits nonsense use the brand
spanking new attr::sched_flags field.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Dario Faggioli <raistlin@linux.it>
Link: http://lkml.kernel.org/r/20140115162242.GJ31570@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fengguang Wu reported the following build warning:
> kernel/sched/core.c:3067 __sched_setscheduler() warn: unsigned 'attr->sched_priority' is never less than zero.
Since it doesn't make sense for attr::sched_priority to be negative,
remove the check, since we already test for an upper limit any actual
negative values passed in through the old param::sched_priority field
will still be detected.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Dario Faggioli <raistlin@linux.it>
Fixes: d50dde5a10 ("sched: Add new scheduler syscalls to support an extended scheduling parameters ABI")
Link: http://lkml.kernel.org/n/tip-fid9nalzii2r5voxtf4eh5kz@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Wu reported LTP failures:
> ltp.sched_setparam02.1.TFAIL
> ltp.sched_setparam02.2.TFAIL
> ltp.sched_setparam02.3.TFAIL
> ltp.sched_setparam03.1.TFAIL
There were 2 things wrong; firstly __setscheduler() failed on
sched_setparam()'s policy = -1, fix that by reading from p->policy in
that case.
Secondly, getparam() (and getattr()) would still report !0
sched_priority for !FIFO/RR tasks after having been such. So
unconditionally set p->rt_priority.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Dario Faggioli <raistlin@linux.it>
Fixes: d50dde5a10 ("sched: Add new scheduler syscalls to support an extended scheduling parameters ABI")
Link: http://lkml.kernel.org/r/20140115153320.GH31570@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Previously sched_setscheduler() and sched_setparam() would not affect
the nice value of a task, restore this behaviour.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: raistlin@linux.it
Cc: juri.lelli@gmail.com
Cc: Michael wang <wangyun@linux.vnet.ibm.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Fixes: d50dde5a10 ("sched: Add new scheduler syscalls to support an extended scheduling parameters ABI")
Link: http://lkml.kernel.org/r/20140115113015.GB31570@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fengguang Wu's kbuild test robot reported the following new htmldocs warnings:
>>> Warning(kernel/sched/core.c:3380): No description found for parameter 'uattr'
>>> Warning(kernel/sched/core.c:3380): Excess function parameter 'attr' description in 'sys_sched_setattr'
>>> Warning(kernel/sched/core.c:3520): No description found for parameter 'uattr'
>>> Warning(kernel/sched/core.c:3520): Excess function parameter 'attr' description in 'sys_sched_getattr'
The second argument to sys_sched_{setattr,getattr}() is named uattr (not attr).
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Dario Faggioli <raistlin@linux.it>
Fixes: d50dde5a10 ("sched: Add new scheduler syscalls to support an extended scheduling parameters ABI")
Link: http://lkml.kernel.org/r/52D5552D.5000102@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Dan Carpenter reported new 'Smatch' warnings:
> tree: git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/core
> head: 130816ce4d
> commit: 1baca4ce16 [17/50] sched/deadline: Add SCHED_DEADLINE SMP-related data structures & logic
>
> kernel/sched/deadline.c:937 pick_next_task_dl() warn: variable dereferenced before check 'p' (see line 934)
BUG_ON() already fires if pick_next_dl_entity() doesn't return a valid
dl_se. No need to check if p is valid afterward.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Fixes: 1baca4ce16 ("sched/deadline: Add SCHED_DEADLINE SMP-related data structures & logic")
Link: http://lkml.kernel.org/r/52D54E25.6060100@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
fix these new sparse warnings:
>> kernel/sched/core.c:305:14: sparse: symbol 'sysctl_sched_dl_period' was not declared. Should it be static?
>> kernel/sched/core.c:306:5: sparse: symbol 'sysctl_sched_dl_runtime' was not declared. Should it be static?
Better still, they're completely unused so remove them.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Link: http://lkml.kernel.org/n/tip-ke0shkG7vMnzmcdqhhiymyem@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
new sparse warnings:
>> kernel/sched/cpudeadline.c:38:6: sparse: symbol 'cpudl_exchange' was not declared. Should it be static?
>> kernel/sched/cpudeadline.c:46:6: sparse: symbol 'cpudl_heapify' was not declared. Should it be static?
>> kernel/sched/cpudeadline.c:71:6: sparse: symbol 'cpudl_change_key' was not declared. Should it be static?
>> kernel/sched/cpudeadline.c:195:15: sparse: memset with byte count of 163928
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Fixes: 6bfd6d72f5 ("sched/deadline: speed up SCHED_DEADLINE pushes with a push-heap")
Link: http://lkml.kernel.org/r/52d47f8c.EYJsA5+mELPBk4t6\%fengguang.wu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
While calculating the scheduler tick max deferment, the delta is
converted from microseconds to nanoseconds through a multiplication
against NSEC_PER_USEC.
But this microseconds operand is an unsigned int, thus the result may
likely overflow. The result is cast to u64 but only once the operation
is completed, which is too late to avoid overflown result.
This is currently not a problem because the scheduler tick max deferment
is 1 second. But this may become an issue as we plan to make this
value tunable.
So lets fix this by casting the usecs value to u64 before multiplying by
NSECS_PER_USEC.
Also to prevent from this kind of mistake to happen again, move this
ad-hoc jiffies -> nsecs conversion to a new helper.
Signed-off-by: Kevin Hilman <khilman@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alex Shi <alex.shi@linaro.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Kevin Hilman <khilman@linaro.org>
Link: http://lkml.kernel.org/r/1387315388-31676-2-git-send-email-khilman@linaro.org
[move ad-hoc conversion to jiffies_to_nsecs helper]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
With various drivers wanting to inject idle time; we get people
calling idle routines outside of the idle loop proper.
Therefore we need to be extra careful about not missing
TIF_NEED_RESCHED -> PREEMPT_NEED_RESCHED propagations.
While looking at this, I also realized there's a small window in the
existing idle loop where we can miss TIF_NEED_RESCHED; when it hits
right after the tif_need_resched() test at the end of the loop but
right before the need_resched() test at the start of the loop.
So move preempt_fold_need_resched() out of the loop where we're
guaranteed to have TIF_NEED_RESCHED set.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-x9jgh45oeayzajz2mjt0y7d6@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Nicolas Pitre
Alex Shi
Dietmar Eggemann
Peter Zijlstra
Daniel Lezcano
Dongsheng Yang
Kirill Tkhai
Ingo Molnar
Linus Torvalds
Rik van Riel
Dario Faggioli
Andi Kleen
Vincent Guittot
Mel Gorman
Juri Lelli
Fengguang Wu
Kevin Hilman