Messages in this thread Patch in this message | | | Date | Wed, 29 Mar 2006 19:54:53 -0500 | From | Shailabh Nagar <> | Subject | [Patch 6/8] virtual cpu run time |
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delayacct-virtcpu.patch
Distinguish between "wall-clock" and "virtual" cpu run times and return both, at per-task and per-tgid granularity.
Some architectures adjust tsk->utime+tsk->stime to reflect the time that the kernel wasn't scheduled in hypervised environments and this is the "wall-clock" cpu run time. "Virtual" cpu run time, on the other hand, does not account for the kernel being descheduled.
This patch allows the most accurate "virtual" cpu run time, collected by the schedstats code (now shared with delay accounting code), to be returned to user space, in addition to the "wall-clock" cpu time that was being exported earlier. Both these times are useful for workload management in different situations.
In a non-virtualized environment, or on architectures which do not adjust tsk->utime/stime, these will effectively be the same value but at different granularities.
Signed-off-by: Shailabh Nagar <nagar@us.ibm.com> Signed-off-by: Balbir Singh <balbir@in.ibm.com>
include/linux/taskstats.h | 10 ++++++++-- kernel/delayacct.c | 12 +++++++++--- 2 files changed, 17 insertions(+), 5 deletions(-)
Index: linux-2.6.16/include/linux/taskstats.h =================================================================== --- linux-2.6.16.orig/include/linux/taskstats.h 2006-03-29 18:13:18.000000000 -0500 +++ linux-2.6.16/include/linux/taskstats.h 2006-03-29 18:13:20.000000000 -0500 @@ -46,8 +46,14 @@ struct taskstats { __u64 swapin_count; __u64 swapin_delay_total; /* swapin page fault wait*/
- __u64 cpu_run_total; /* cpu running time - * no count available/provided */ + __u64 cpu_run_real_total; /* cpu "wall-clock" running time + * Potentially accounts for cpu + * virtualization, on some arches + */ + __u64 cpu_run_virtual_total; /* cpu "virtual" running time + * Uses time intervals as seen by + * the kernel + */ };
Index: linux-2.6.16/kernel/delayacct.c =================================================================== --- linux-2.6.16.orig/kernel/delayacct.c 2006-03-29 18:13:18.000000000 -0500 +++ linux-2.6.16/kernel/delayacct.c 2006-03-29 18:13:20.000000000 -0500 @@ -123,17 +123,18 @@ int __delayacct_add_tsk(struct taskstats { nsec_t tmp; struct timespec ts; - unsigned long t1,t2; + unsigned long t1,t2,t3;
/* zero XXX_total,non-zero XXX_count implies XXX stat overflowed */
- tmp = (nsec_t)d->cpu_run_total ; + tmp = (nsec_t)d->cpu_run_real_total ; tmp += (u64)(tsk->utime+tsk->stime)*TICK_NSEC; - d->cpu_run_total = (tmp < (nsec_t)d->cpu_run_total)? 0: tmp; + d->cpu_run_real_total = (tmp < (nsec_t)d->cpu_run_real_total)? 0: tmp;
/* No locking available for sched_info. Take snapshot first. */ t1 = tsk->sched_info.pcnt; t2 = tsk->sched_info.run_delay; + t3 = tsk->sched_info.cpu_time;
d->cpu_count += t1;
@@ -141,6 +142,11 @@ int __delayacct_add_tsk(struct taskstats tmp = (nsec_t)d->cpu_delay_total + timespec_to_ns(&ts); d->cpu_delay_total = (tmp < (nsec_t)d->cpu_delay_total)? 0: tmp;
+ tmp = (nsec_t)d->cpu_run_virtual_total + + (nsec_t)jiffies_to_usecs(t3) * 1000; + d->cpu_run_virtual_total = (tmp < (nsec_t)d->cpu_run_virtual_total) ? + 0 : tmp; + spin_lock(&tsk->delays->lock); tmp = d->blkio_delay_total + tsk->delays->blkio_delay; d->blkio_delay_total = (tmp < d->blkio_delay_total)? 0: tmp; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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