linux.git/kernel/sched_stats.h, branch v2.6.26-rc7

sched, delay accounting: fix incorrect delay time when constantly waiting on runqueue

2008-06-19T12:15:28+00:00

This patch corrects the incorrect value of per process run-queue wait
time reported by delay statistics. The anomaly was due to the following
reason. When a process leaves the CPU and immediately starts waiting for
CPU on the runqueue (which means it remains in the TASK_RUNNABLE state),
the time of re-entry into the run-queue is never recorded. Due to this,
the waiting time on the runqueue from this point of re-entry upto the
next time it hits the CPU is not accounted for. This is solved by
recording the time of re-entry of a process leaving the CPU in the
sched_info_depart() function IF the process will go back to waiting on
the run-queue. This IF condition is verified by checking whether the
process is still in the TASK_RUNNABLE state.

The patch was tested on 2.6.26-rc6 using two simple CPU hog programs.
The values noted prior to the fix did not account for the time spent on
the runqueue waiting. After the fix, the correct values were reported
back to user space.

Signed-off-by: Bharath Ravi 
Signed-off-by: Madhava K R  
Cc: dhaval@linux.vnet.ibm.com
Cc: vatsa@in.ibm.com
Cc: balbir@in.ibm.com
Acked-by: Peter Zijlstra 
Signed-off-by: Ingo Molnar

show_schedstat(): fix memleak

2008-05-29T09:25:15+00:00

The Coverity checker spotted a memleak introduced by commit
39106dcf85285e78f3b290022122c76f851379b8 (cpumask: use new cpus_scnprintf
function).

It seems the kfree() got lost between v2 and v3 of this patch...

Signed-off-by: Adrian Bunk 
Cc: Mike Travis 
Signed-off-by: Andrew Morton 
Signed-off-by: Ingo Molnar

cpumask: use new cpus_scnprintf function

2008-04-19T17:44:59+00:00

  * Cleaned up references to cpumask_scnprintf() and added new
    cpulist_scnprintf() interfaces where appropriate.

  * Fix some small bugs (or code efficiency improvments) for various uses
    of cpumask_scnprintf.

  * Clean up some checkpatch errors.

Signed-off-by: Mike Travis 
Signed-off-by: Ingo Molnar

sched: clean up kernel/sched_stat.h

2007-11-28T14:52:56+00:00

clean up kernel/sched_stat.h.

Signed-off-by: Ingo Molnar

sched: fix delay accounting regression

2007-11-09T21:39:37+00:00

Fix the delay accounting regression introduced by commit
75d4ef16a6aa84f708188bada182315f80aab6fa. rq no longer has sched_info
data associated with it. task_struct sched_info structure is used by delay
accounting to provide back statistics to user space.

also remove direct use of sched_clock() (which is not a valid thing to
do anymore) and use rq->clock instead.

Signed-off-by: Balbir Singh 
Signed-off-by: Ingo Molnar

sched: reduce schedstat variable overhead a bit

2007-10-18T19:32:56+00:00

schedstat is useful in investigating CPU scheduler behavior.  Ideally,
I think it is beneficial to have it on all the time.  However, the
cost of turning it on in production system is quite high, largely due
to number of events it collects and also due to its large memory
footprint.

Most of the fields probably don't need to be full 64-bit on 64-bit
arch.  Rolling over 4 billion events will most like take a long time
and user space tool can be made to accommodate that.  I'm proposing
kernel to cut back most of variable width on 64-bit system.  (note,
the following patch doesn't affect 32-bit system).

Signed-off-by: Ken Chen 
Signed-off-by: Ingo Molnar

sched: clean up schedstats, cnt -> count

2007-10-15T15:00:12+00:00

rename all 'cnt' fields and variables to the less yucky 'count' name.

yuckage noticed by Andrew Morton.

no change in code, other than the /proc/sched_debug bkl_count string got
a bit larger:

   text    data     bss     dec     hex filename
  38236    3506      24   41766    a326 sched.o.before
  38240    3506      24   41770    a32a sched.o.after

Signed-off-by: Ingo Molnar 
Reviewed-by: Thomas Gleixner

sched: fix delay accounting performance regression

2007-10-15T15:00:08+00:00

fix delay accounting performance regression - those sched_clock()
calls are not needed.

Signed-off-by: Ingo Molnar 
Signed-off-by: Peter Zijlstra 
Reviewed-by: Thomas Gleixner

[PATCH] sched: add schedstat_set() API

2007-08-02T15:41:40+00:00

add the schedstat_set() API, to allow the reduction of
CONFIG_SCHEDSTAT related #ifdefs. No code changed.

Signed-off-by: Ingo Molnar

sched: update delay-accounting to use CFS's precise stats

2007-07-09T16:52:00+00:00

update delay-accounting to use CFS's precise stats.

Signed-off-by: Ingo Molnar