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  1. 11 12月, 2016 5 次提交
    • V
      sched/core: Use load_avg for selecting idlest group · 6b94780e
      由 Vincent Guittot 提交于 
      find_idlest_group() only compares the runnable_load_avg when looking
for the least loaded group. But on fork intensive use case like
hackbench where tasks blocked quickly after the fork, this can lead to
selecting the same CPU instead of other CPUs, which have similar
runnable load but a lower load_avg.

When the runnable_load_avg of 2 CPUs are close, we now take into
account the amount of blocked load as a 2nd selection factor. There is
now 3 zones for the runnable_load of the rq:

 - [0 .. (runnable_load - imbalance)]:
	Select the new rq which has significantly less runnable_load

 - [(runnable_load - imbalance) .. (runnable_load + imbalance)]:
	The runnable loads are close so we use load_avg to chose
	between the 2 rq

 - [(runnable_load + imbalance) .. ULONG_MAX]:
	Keep the current rq which has significantly less runnable_load

The scale factor that is currently used for comparing runnable_load,
doesn't work well with small value. As an example, the use of a
scaling factor fails as soon as this_runnable_load == 0 because we
always select local rq even if min_runnable_load is only 1, which
doesn't really make sense because they are just the same. So instead
of scaling factor, we use an absolute margin for runnable_load to
detect CPUs with similar runnable_load and we keep using scaling
factor for blocked load.

For use case like hackbench, this enable the scheduler to select
different CPUs during the fork sequence and to spread tasks across the
system.

Tests have been done on a Hikey board (ARM based octo cores) for
several kernel. The result below gives min, max, avg and stdev values
of 18 runs with each configuration.

The patches depend on the "no missing update_rq_clock()" work.

hackbench -P -g 1

         ea86cb4b  7dc603c9  v4.8        v4.8+patches
  min    0.049         0.050         0.051       0,048
  avg    0.057         0.057(0%)     0.057(0%)   0,055(+5%)
  max    0.066         0.068         0.070       0,063
  stdev  +/-9%         +/-9%         +/-8%       +/-9%

More performance numbers here:

  https://lkml.kernel.org/r/20161203214707.GI20785@codeblueprint.co.ukTested-by: NMatt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NMatt Fleming <matt@codeblueprint.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Morten.Rasmussen@arm.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: kernellwp@gmail.com
Cc: umgwanakikbuti@gmail.com
Cc: yuyang.du@intel.comc
Link: http://lkml.kernel.org/r/1481216215-24651-3-git-send-email-vincent.guittot@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      6b94780e
    • V
      sched/core: Fix find_idlest_group() for fork · f519a3f1
      由 Vincent Guittot 提交于 
      During fork, the utilization of a task is init once the rq has been
selected because the current utilization level of the rq is used to
set the utilization of the fork task. As the task's utilization is
still 0 at this step of the fork sequence, it doesn't make sense to
look for some spare capacity that can fit the task's utilization.
Furthermore, I can see perf regressions for the test:

   hackbench -P -g 1

because the least loaded policy is always bypassed and tasks are not
spread during fork.

With this patch and the fix below, we are back to same performances as
for v4.8. The fix below is only a temporary one used for the test
until a smarter solution is found because we can't simply remove the
test which is useful for others benchmarks

| @@ -5708,13 +5708,6 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t
|
|	avg_cost = this_sd->avg_scan_cost;
|
| -	/*
| -	 * Due to large variance we need a large fuzz factor; hackbench in
| -	 * particularly is sensitive here.
| -	 */
| -	if ((avg_idle / 512) < avg_cost)
| -		return -1;
| -
|	time = local_clock();
|
|	for_each_cpu_wrap(cpu, sched_domain_span(sd), target, wrap) {
Tested-by: NMatt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NMatt Fleming <matt@codeblueprint.co.uk>
Acked-by: NMorten Rasmussen <morten.rasmussen@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: kernellwp@gmail.com
Cc: umgwanakikbuti@gmail.com
Cc: yuyang.du@intel.comc
Link: http://lkml.kernel.org/r/1481216215-24651-2-git-send-email-vincent.guittot@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      f519a3f1
    • I
      Merge branch 'linus' into sched/core, to pick up fixes · 6643aab3
      由 Ingo Molnar 提交于 
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      6643aab3
    • L
      Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 · 04516981
      由 Linus Torvalds 提交于 
      Pull crypto fixes from Herbert Xu:
 "This fixes the following issues:

   - Fix pointer size when caam is used with AArch64 boot loader on
     AArch32 kernel.

   - Fix ahash state corruption in marvell driver.

   - Fix buggy algif_aed tag handling.

   - Prevent mcryptd from being used with incompatible algorithms which
     can cause crashes"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: algif_aead - fix uninitialized variable warning
  crypto: mcryptd - Check mcryptd algorithm compatibility
  crypto: algif_aead - fix AEAD tag memory handling
  crypto: caam - fix pointer size for AArch64 boot loader, AArch32 kernel
  crypto: marvell - Don't corrupt state of an STD req for re-stepped ahash
  crypto: marvell - Don't copy hash operation twice into the SRAM
      04516981
    • L
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net · cd662895
      由 Linus Torvalds 提交于 
      Pull networking fixes from David Miller:

 1) Limit the number of can filters to avoid > MAX_ORDER allocations.
    Fix from Marc Kleine-Budde.

 2) Limit GSO max size in netvsc driver to avoid problems with NVGRE
    configurations. From Stephen Hemminger.

 3) Return proper error when memory allocation fails in
    ser_gigaset_init(), from Dan Carpenter.

 4) Missing linkage undo in error paths of ipvlan_link_new(), from Gao
    Feng.

 5) Missing necessayr SET_NETDEV_DEV in lantiq and cpmac drivers, from
    Florian Fainelli.

 6) Handle probe deferral properly in smsc911x driver.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  net: mlx5: Fix Kconfig help text
  net: smsc911x: back out silently on probe deferrals
  ibmveth: set correct gso_size and gso_type
  net: ethernet: cpmac: Call SET_NETDEV_DEV()
  net: ethernet: lantiq_etop: Call SET_NETDEV_DEV()
  vhost-vsock: fix orphan connection reset
  cxgb4/cxgb4vf: Assign netdev->dev_port with port ID
  driver: ipvlan: Unlink the upper dev when ipvlan_link_new failed
  ser_gigaset: return -ENOMEM on error instead of success
  NET: usb: cdc_mbim: add quirk for supporting Telit LE922A
  can: peak: fix bad memory access and free sequence
  phy: Don't increment MDIO bus refcount unless it's a different owner
  netvsc: reduce maximum GSO size
  drivers: net: cpsw-phy-sel: Clear RGMII_IDMODE on "rgmii" links
  can: raw: raw_setsockopt: limit number of can_filter that can be set
      cd662895
  3. 10 12月, 2016 10 次提交
  5. 09 12月, 2016 13 次提交
  7. 08 12月, 2016 12 次提交