linux-toradex.git/kernel/sched_debug.c, branch v2.6.25-rc2

sched: keep total / count stats in addition to the max for

2008-01-25T20:08:35+00:00

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 
Signed-off-by: Ingo Molnar

sched: monitor clock underflows in /proc/sched_debug

2008-01-25T20:08:34+00:00

We monitor clock overflows, let's also monitor clock underflows.

Signed-off-by: Guillaume Chazarain 
Signed-off-by: Ingo Molnar

sched: fix gcc warnings

2007-12-30T16:24:35+00:00

Meelis Roos reported these warnings on sparc64:

  CC      kernel/sched.o
  In file included from kernel/sched.c:879:
  kernel/sched_debug.c: In function 'nsec_high':
  kernel/sched_debug.c:38: warning: comparison of distinct pointer types lacks a cast

the debug check in do_div() is over-eager here, because the long long
is always positive in these places. Mark this by casting them to
unsigned long long.

no change in code output:

   text    data     bss     dec     hex filename
  51471    6582     376   58429    e43d sched.o.before
  51471    6582     376   58429    e43d sched.o.after

  md5:
   7f7729c111f185bf3ccea4d542abc049  sched.o.before.asm
   7f7729c111f185bf3ccea4d542abc049  sched.o.after.asm

Signed-off-by: Ingo Molnar

sched: clean up overlong line in kernel/sched_debug.c

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

clean up overlong line in kernel/sched_debug.c.

Signed-off-by: Ingo Molnar

sched: bump version of kernel/sched_debug.c

2007-11-26T20:21:49+00:00

bump version of kernel/sched_debug.c and remove CFS version
information from it.

Signed-off-by: Ingo Molnar

sched: reintroduce the sched_min_granularity tunable

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

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 
Signed-off-by: Ingo Molnar

sched: fix unconditional irq lock

2007-10-25T12:02:45+00:00

Lockdep noticed that this lock can also be taken from hardirq context, and can
thus not unconditionally disable/enable irqs.

 WARNING: at kernel/lockdep.c:2033 trace_hardirqs_on()
  [show_trace_log_lvl+26/48] show_trace_log_lvl+0x1a/0x30
  [show_trace+18/32] show_trace+0x12/0x20
  [dump_stack+22/32] dump_stack+0x16/0x20
  [trace_hardirqs_on+405/416] trace_hardirqs_on+0x195/0x1a0
  [_read_unlock_irq+34/48] _read_unlock_irq+0x22/0x30
  [sched_debug_show+2615/4224] sched_debug_show+0xa37/0x1080
  [show_state_filter+326/368] show_state_filter+0x146/0x170
  [sysrq_handle_showstate+10/16] sysrq_handle_showstate+0xa/0x10
  [__handle_sysrq+123/288] __handle_sysrq+0x7b/0x120
  [handle_sysrq+40/64] handle_sysrq+0x28/0x40
  [kbd_event+1045/1680] kbd_event+0x415/0x690
  [input_pass_event+206/208] input_pass_event+0xce/0xd0
  [input_handle_event+170/928] input_handle_event+0xaa/0x3a0
  [input_event+95/112] input_event+0x5f/0x70
  [atkbd_interrupt+434/1456] atkbd_interrupt+0x1b2/0x5b0
  [serio_interrupt+59/128] serio_interrupt+0x3b/0x80
  [i8042_interrupt+263/576] i8042_interrupt+0x107/0x240
  [handle_IRQ_event+40/96] handle_IRQ_event+0x28/0x60
  [handle_edge_irq+175/320] handle_edge_irq+0xaf/0x140
  [do_IRQ+64/128] do_IRQ+0x40/0x80
  [common_interrupt+46/52] common_interrupt+0x2e/0x34

Signed-off-by: Peter Zijlstra 
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

Make scheduler debug file operations const

2007-10-15T15:00:19+00:00

In general, struct file_operations are const in the kernel, to not have
false cacheline sharing and to catch bugs at compiletime with accidental
writes to them. The new scheduler code introduces a new non-const one;
fix this up.

Signed-off-by: Arjan van de Ven 
Signed-off-by: Ingo Molnar

sched: debug, improve migration statistics

2007-10-15T15:00:18+00:00

add new migration statistics when SCHED_DEBUG and SCHEDSTATS
is enabled. Available in /proc//sched.

Signed-off-by: Ingo Molnar