Messages in this thread | | | Date | Tue, 2 Jun 2015 09:58:25 +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 11:54AM, Ingo Molnar wrote: > > > > > > 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. > > Per Documentation/scheduler/sched-stats.txt (and the linked latency.c there), > user-space seems to be expecting unsigned values here. Would displaying -1 here > be ok?
Probably not (the code is silly, why doesn't it split up the string and use atol()?) - hopefully real user-space is better? Can you try some real, packaged up tools that read schedstats, to see whether they work with -1?
Thanks,
Ingo
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