Messages in this thread | | | Date | Thu, 30 Mar 2006 11:10:44 -0500 | From | Shailabh Nagar <> | Subject | Re: [Patch 6/8] virtual cpu run time |
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Andrew Morton wrote:
>Shailabh Nagar <nagar@watson.ibm.com> wrote: > > >>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. >> >>... >> >>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 >>+ */ >> }; >> >> >> > >Again, the reader of this struct wants to know what the atomicity rules are. > > Will add comment.
> > >>+ d->cpu_run_real_total = (tmp < (nsec_t)d->cpu_run_real_total)? 0: tmp; >> >> > > lval = expr1 ? expr2 : expr3; > > didn't get whats wrong ?
> > >>+ tmp = (nsec_t)d->cpu_run_virtual_total >>+ + (nsec_t)jiffies_to_usecs(t3) * 1000; >> >> > >umm, Linux doesn't have nsec_t any more. > > > Ok, will switch to s64 everywhere.
--Shailabh
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