* Naveen N. Rao <naveen.n....@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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