Messages in this thread | | | Date | Fri, 29 May 2015 11:54:35 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] proc/schedstat: Expose /proc/<pid>/schedstat if delay accounting is enabled |
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* Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> wrote:
> On 2015/05/29 11:18AM, Ingo Molnar wrote: > > > > * Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> wrote: > > > > > On 2015/05/29 10:04AM, Ingo Molnar wrote: > > > > > > > > * Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> wrote: > > > > > > > > - The sum_exec_runtime field is available unconditionally. > > > > > > > > - But the sched_info.run_delay field is only maintained if CONFIG_SCHEDSTATS is > > > > enabled. > > > > > > > > - Also, the sched_info.pcount field is again only maintained if CONFIG_SCHEDSTATS > > > > is enabled. > > > > > > I may be missing something, but from my reading of the code, the above > > > are maintained if any one of CONFIG_SCHEDSTATS or CONFIG_TASK_DELAY_ACCT > > > are enabled (from kernel/sched/stats.h). > > > > Hm, indeed - I mis-read the rq-specific code - sorry. > > > > So all this should really be cleaned up: > > > > include/linux/sched.h:#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) > > include/linux/sched.h:#endif /* defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) */ > > include/linux/sched.h:#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) > > kernel/sched/core.c:#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) > > kernel/sched/stats.h:#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) > > kernel/sched/stats.h:#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */ > > > > by introducing an intermediate Kconfig variable, named CONFIG_SCHED_INFO or so, > > and selected by both SCHEDSTATS and TASK_DELAY_ACCT. > > > > Please make it two patches: the first one adds CONFIG_SCHED_INFO and cleans up the > > code to use it, the second one uses it for the procps change. > > Sure, will do. > > On a related note, even though sum_exec_runtime is available unconditionally, I > dump all zeroes in my patch if !sched_info_on() to make it clear that some of > the fields are not available. Is this ok or should be display sum_exec_runtime > regardless of sched_info?
So I'd suggest printing -1 for non-available fields, that should be unambigous enough and makes it also possible to write out 0 in some cases.
That way the schedstat file should be made unconditional altogether. (And we still want the Kconfig cleanups as a separate patch.)
Thanks,
Ingo
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