Vincent Guittot
05bfb65f52
sched: Remove a wake_affine() condition ...
In wake_affine() I have tried to understand the meaning of the condition:
(this_load <= load &&
this_load + target_load(prev_cpu, idx) <= tl_per_task)
but I failed to find a use case that can take advantage of it and I haven't
found clear description in the previous commit's log.
Futhermore, the comment of the condition refers to the task_hot function that
was used before being replaced by the current condition:
/*
* This domain has SD_WAKE_AFFINE and
* p is cache cold in this domain, and
* there is no bad imbalance.
*/
If we look more deeply the below condition:
this_load + target_load(prev_cpu, idx) <= tl_per_task
When sync is clear, we have:
tl_per_task = runnable_load_avg / nr_running
this_load = max(runnable_load_avg, cpuload[idx])
target_load = max(runnable_load_avg', cpuload'[idx])
It implies that runnable_load_avg == 0 and nr_running <= 1 in order to match the
condition. This implies that runnable_load_avg == 0 too because of the
condition: this_load <= load.
but if this _load is null, 'balanced' is already set and the test is redundant.
If sync is set, it's not as straight forward as above (especially if cgroup
are involved) but the policy should be similar as we have removed a task that's
going to sleep in order to get a more accurate load and this_load values.
The current conclusion is that these additional condition don't give any benefit
so we can remove them.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: preeti@linux.vnet.ibm.com
Cc: riel@redhat.com
Cc: Morten.Rasmussen@arm.com
Cc: efault@gmx.de
Cc: nicolas.pitre@linaro.org
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409051215-16788-3-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-19 12:35:25 +02:00
net: filter: split 'struct sk_filter' into socket and bpf parts
2014-08-02 15:03:58 -07:00
kdb: Use ktime_get_ts()
2014-06-12 16:18:45 +02:00
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-08-24 16:16:55 -07:00
kernel/gcov/fs.c: remove unnecessary null test before debugfs_remove
2014-08-08 15:57:24 -07:00
irq: Export handle_fasteoi_irq
2014-08-25 21:13:30 +02:00
arch, locking: Ciao arch_mutex_cpu_relax()
2014-07-17 12:32:47 +02:00
PM / sleep: Fix test_suspend= command line option
2014-09-03 01:21:03 +02:00
printk: Add function to return log buffer address and size
2014-08-13 15:13:44 +10:00
rcu: Make nocb leader kthreads process pending callbacks after spawning
2014-08-28 05:59:59 -07:00
sched: Remove a wake_affine() condition
2014-09-19 12:35:25 +02:00
sched, cleanup, treewide: Remove set_current_state(TASK_RUNNING) after schedule()
2014-09-19 12:35:17 +02:00
sched: Add helper for task stack page overrun checking
2014-09-19 12:35:23 +02:00
kernel/acct.c: fix coding style warnings and errors
2014-08-08 15:57:27 -07:00
CAPABILITIES: remove undefined caps from all processes
2014-07-24 21:53:47 +10:00
kernel/auditfilter.c: replace count*size kmalloc by kcalloc
2014-08-06 18:01:12 -07:00
auditsc: audit_krule mask accesses need bounds checking
2014-06-10 08:44:40 -07:00
kernel/backtracetest.c: replace no level printk by pr_info()
2014-06-04 16:54:14 -07:00
page-cgroup: get rid of NR_PCG_FLAGS
2014-08-08 15:57:18 -07:00
CAPABILITIES: remove undefined caps from all processes
2014-07-24 21:53:47 +10:00
Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2014-08-04 10:11:28 -07:00
cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes
2014-07-15 11:05:09 -04:00
compat: nanosleep: Clarify error handling
2014-09-06 12:58:18 +02:00
x86/kprobes: Fix build errors and blacklist context_track_user
2014-06-14 09:07:44 +02:00
sched: Rework check_for_tasks()
2014-07-05 11:17:45 +02:00
Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2014-08-04 10:11:28 -07:00
delayacct: Remove braindamaged type conversions
2014-07-23 10:18:06 -07:00
kernel/exec_domain.c: code clean-up
2014-06-04 16:54:15 -07:00
time, signal: Protect resource use statistics with seqlock
2014-09-08 08:17:01 +02:00
init/main.c: Give init_task a canary
2014-09-19 12:35:22 +02:00
futex: Simplify futex_lock_pi_atomic() and make it more robust
2014-06-21 22:26:24 +02:00
kernel/hung_task.c: convert simple_strtoul to kstrtouint
2014-06-04 16:54:15 -07:00
irq_work: Remove BUG_ON in irq_work_run()
2014-07-05 11:17:26 +02:00
kernel/kallsyms.c: fix %pB when there's no symbol at the address
2014-08-08 15:57:18 -07:00
locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER
2014-07-16 14:57:13 +02:00
kexec: create a new config option CONFIG_KEXEC_FILE for new syscall
2014-08-29 16:28:16 -07:00
signals: change wait_for_helper() to use kernel_sigaction()
2014-06-06 16:08:12 -07:00
kprobes: Skip kretprobe hit in NMI context to avoid deadlock
2014-08-08 10:38:04 +02:00
kthread_work: wake up worker only when the worker is idle
2014-07-28 14:07:52 -04:00
kernel/latencytop.c: convert seq_printf to seq_puts
2014-06-04 16:54:15 -07:00
bin2c: move bin2c in scripts/basic
2014-08-08 15:57:32 -07:00
module: Clean up ro/nx after early module load failures
2014-08-16 04:47:00 +09:30
namespaces: Use task_lock and not rcu to protect nsproxy
2014-07-29 18:08:50 -07:00
panic: add TAINT_SOFTLOCKUP
2014-08-08 15:57:24 -07:00
Add module param type 'ullong'
2014-07-17 22:07:37 +02:00
kernel/profile.c: use static const char instead of static char
2014-06-06 16:08:13 -07:00
sched: Remove proliferation of wait_on_bit() action functions
2014-07-16 15:10:39 +02:00
kernel/reboot.c: convert simple_strtoul to kstrtoint
2014-06-04 16:54:15 -07:00
kernel/res_counter.c: replace simple_strtoull by kstrtoull
2014-06-04 16:54:15 -07:00
resource: fix the case of null pointer access
2014-08-29 16:28:15 -07:00
seccomp: Replace BUG(!spin_is_locked()) with assert_spin_lock
2014-08-11 13:29:12 -07:00
Merge branch 'signal-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc
2014-08-09 09:58:12 -07:00
smp: Add new wake_up_all_idle_cpus() function
2014-09-19 12:35:15 +02:00
kernel/stop_machine.c: kernel-doc warning fix
2014-06-04 16:54:15 -07:00
time, signal: Protect resource use statistics with seqlock
2014-09-08 08:17:01 +02:00
kexec: new syscall kexec_file_load() declaration
2014-08-08 15:57:32 -07:00
mm, hugetlb: remove hugetlb_zero and hugetlb_infinity
2014-08-06 18:01:19 -07:00
ipv6: Allow accepting RA from local IP addresses.
2014-07-01 12:16:24 -07:00
KEYS: validate certificate trust only with builtin keys
2014-07-17 09:35:17 -04:00
kernel/test_kprobes.c: use current logging functions
2014-08-08 15:57:18 -07:00
torture: Avoid format string leak to thead name
2014-07-07 10:12:56 -07:00
tracing: syscall_regfunc() should not skip kernel threads
2014-06-21 00:15:26 -04:00
sched: Make task->start_time nanoseconds based
2014-07-23 10:18:05 -07:00
kernel/user.c: drop unused field 'files' from user_struct
2014-06-04 16:54:16 -07:00
proc: constify seq_operations
2014-08-08 15:57:22 -07:00
namespaces: Use task_lock and not rcu to protect nsproxy
2014-07-29 18:08:50 -07:00
sysctl: convert use of typedef ctl_table to struct ctl_table
2014-06-06 16:08:16 -07:00
panic: add TAINT_SOFTLOCKUP
2014-08-08 15:57:24 -07:00
Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2014-08-04 10:09:27 -07:00
05bfb65f52