linux-toradex.git/kernel/tsacct.c, branch v4.13-rc5

sched/headers: Prepare to move cputime functionality from into

2017-03-02T07:42:39+00:00

Introduce a trivial, mostly empty  header
to prepare for the moving of cputime functionality out of sched.h.

Update all code that relies on these facilities.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:29+00:00

We are going to split  out of , which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder  file that just
maps to  to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:28+00:00

We are going to split  out of , which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder  file that just
maps to  to make this patch obviously correct and
bisectable.

The APIs that are going to be moved first are:

   mm_alloc()
   __mmdrop()
   mmdrop()
   mmdrop_async_fn()
   mmdrop_async()
   mmget_not_zero()
   mmput()
   mmput_async()
   get_task_mm()
   mm_access()
   mm_release()

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

tsacct: Convert obsolete cputime type to nsecs

2017-02-01T08:13:52+00:00

Use the new nsec based cputime accessors as part of the whole cputime
conversion from cputime_t to nsecs.

Signed-off-by: Frederic Weisbecker 
Cc: Benjamin Herrenschmidt 
Cc: Fenghua Yu 
Cc: Heiko Carstens 
Cc: Linus Torvalds 
Cc: Martin Schwidefsky 
Cc: Michael Ellerman 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Stanislaw Gruszka 
Cc: Thomas Gleixner 
Cc: Tony Luck 
Cc: Wanpeng Li 
Link: http://lkml.kernel.org/r/1485832191-26889-15-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar

sched/cputime: Introduce special task_cputime_t() API to return old-typed cputime

2017-02-01T08:13:48+00:00

This API returns a task's cputime in cputime_t in order to ease the
conversion of cputime internals to use nsecs units instead. Blindly
converting all cputime readers to use this API now will later let us
convert more smoothly and step by step all these places to use the
new nsec based cputime.

Signed-off-by: Frederic Weisbecker 
Cc: Benjamin Herrenschmidt 
Cc: Fenghua Yu 
Cc: Heiko Carstens 
Cc: Linus Torvalds 
Cc: Martin Schwidefsky 
Cc: Michael Ellerman 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Stanislaw Gruszka 
Cc: Thomas Gleixner 
Cc: Tony Luck 
Cc: Wanpeng Li 
Link: http://lkml.kernel.org/r/1485832191-26889-7-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar

time, acct: Drop irq save & restore from __acct_update_integrals()

2016-02-29T08:53:09+00:00

It looks like all the call paths that lead to __acct_update_integrals()
already have irqs disabled, and __acct_update_integrals() does not need
to disable irqs itself.

This is very convenient since about half the CPU time left in this
function was spent in local_irq_save alone.

Performance of a microbenchmark that calls an invalid syscall
ten million times in a row on a nohz_full CPU improves 21% vs.
4.5-rc1 with both the removal of divisions from __acct_update_integrals()
and this patch, with runtime dropping from 3.7 to 2.9 seconds.

With these patches applied, the highest remaining cpu user in
the trace is native_sched_clock, which is addressed in the next
patch.

For testing purposes I stuck a WARN_ON(!irqs_disabled()) test
in __acct_update_integrals(). It did not trigger.

Suggested-by: Peter Zijlstra 
Signed-off-by: Rik van Riel 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Thomas Gleixner 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: clark@redhat.com
Cc: eric.dumazet@gmail.com
Cc: fweisbec@gmail.com
Cc: luto@amacapital.net
Link: http://lkml.kernel.org/r/1455152907-18495-4-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar

acct, time: Change indentation in __acct_update_integrals()

2016-02-29T08:53:09+00:00

Change the indentation in __acct_update_integrals() to make the function
a little easier to read.

Suggested-by: Peter Zijlstra 
Signed-off-by: Rik van Riel 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Thomas Gleixner 
Acked-by: Frederic Weisbecker 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: clark@redhat.com
Cc: eric.dumazet@gmail.com
Cc: fweisbec@gmail.com
Cc: luto@amacapital.net
Link: http://lkml.kernel.org/r/1455152907-18495-3-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar

sched, time: Remove non-power-of-two divides from __acct_update_integrals()

2016-02-29T08:53:08+00:00

When running a microbenchmark calling an invalid syscall number
in a loop, on a nohz_full CPU, we spend a full 9% of our CPU
time in __acct_update_integrals().

This function converts cputime_t to jiffies, to a timeval, only to
convert the timeval back to microseconds before discarding it.

This patch leaves __acct_update_integrals() functionally equivalent,
but speeds things up by about 12%, with 10 million calls to an
invalid syscall number dropping from 3.7 to 3.25 seconds.

Signed-off-by: Rik van Riel 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Thomas Gleixner 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: clark@redhat.com
Cc: eric.dumazet@gmail.com
Cc: fweisbec@gmail.com
Cc: luto@amacapital.net
Link: http://lkml.kernel.org/r/1455152907-18495-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar

sched: Make task->start_time nanoseconds based

2014-07-23T17:18:05+00:00

Simplify the timespec to nsec/usec conversions.

Signed-off-by: Thomas Gleixner 
Signed-off-by: John Stultz

tsacct: Use ktime_get_ts()

2014-06-12T14:18:45+00:00

do_posix_clock_monotonic_gettime() is a leftover from the initial
posix timer implementation which maps to ktime_get_ts()

Signed-off-by: Thomas Gleixner 
Cc: John Stultz 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20140611234606.840900621@linutronix.de
Signed-off-by: Thomas Gleixner