timers: split process wide cpu clocks/timers

Change the process wide cpu timers/clocks so that we:

 1) don't mess up the kernel with too many threads,
 2) don't have a per-cpu allocation for each process,
 3) have no impact when not used.

In order to accomplish this we're going to split it into two parts:

 - clocks; which can take all the time they want since they run
           from user context -- ie. sys_clock_gettime(CLOCK_PROCESS_CPUTIME_ID)

 - timers; which need constant time sampling but since they're
           explicity used, the user can pay the overhead.

The clock readout will go back to a full sum of the thread group, while the
timers will run of a global 'clock' that only runs when needed, so only
programs that make use of the facility pay the price.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-02-05 12:24:16 +01:00 committed by Ingo Molnar
parent 32bd671d6c
commit 4cd4c1b40d
5 changed files with 155 additions and 54 deletions

View file

@ -48,12 +48,11 @@ extern struct fs_struct init_fs;
.posix_timers = LIST_HEAD_INIT(sig.posix_timers), \
.cpu_timers = INIT_CPU_TIMERS(sig.cpu_timers), \
.rlim = INIT_RLIMITS, \
.cputime = { .totals = { \
.utime = cputime_zero, \
.stime = cputime_zero, \
.sum_exec_runtime = 0, \
.lock = __SPIN_LOCK_UNLOCKED(sig.cputime.totals.lock), \
}, }, \
.cputimer = { \
.cputime = INIT_CPUTIME, \
.running = 0, \
.lock = __SPIN_LOCK_UNLOCKED(sig.cputimer.lock), \
}, \
}
extern struct nsproxy init_nsproxy;