[[PATCH 3/3] cputime: Consolidate cputime adjustment code] On 23/11/2012 (Fri
15:21) Frederic Weisbecker wrote:
> task_cputime_adjusted() and thread_group_cputime_adjusted()
> essentially share the same code. They just don't use the same
> source:
>
> * The first function uses the cputime in the task struct and the
> previous adjusted snapshot that ensures monotonicity.
>
> * The second adds the cputime of all tasks in the group and the
> previous adjusted snapshot of the whole group from the signal
> structure.
>
> Just consolidate the common code that does the adjustment. These
> functions just need to fetch the values from the appropriate
> source.
>
> Signed-off-by: Frederic Weisbecker <fweis...@gmail.com>
> Cc: Ingo Molnar <mi...@kernel.org>
> Cc: Peter Zijlstra <pet...@infradead.org>
> Cc: Thomas Gleixner <t...@linutronix.de>
> Cc: Steven Rostedt <rost...@goodmis.org>
> ---
> include/linux/sched.h | 9 +++++++--
> kernel/fork.c | 2 +-
> kernel/sched/cputime.c | 46 +++++++++++++++++++++++-----------------------
> 3 files changed, 31 insertions(+), 26 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index e75cab5..d23204f 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -433,6 +433,11 @@ struct cpu_itimer {
> u32 incr_error;
> };
>
> +struct cputime {
> + cputime_t utime;
> + cputime_t stime;
> +};
> +
Hi Frederic,
This new struct cputime is a 2/3 subset of the three variable struct
task_cputime we see right below. Maybe this is a stupid question, but I
was wondering why you didn't re-use task_cputime, and ignore the
sum_exec_runtime field -- vs. introducing this very similar struct?
Or maybe there is another way to consolidate the structs? With the
two being so similar, I wonder if it will be confusing when to use which
one of the two.
Thanks,
Paul.
--
/**
* struct task_cputime - collected CPU time counts
* @utime: time spent in user mode, in &cputime_t units
* @stime: time spent in kernel mode, in &cputime_t units
* @sum_exec_runtime: total time spent on the CPU, in nanoseconds
*
* This structure groups together three kinds of CPU time that are
* tracked for threads and thread groups. Most things considering
* CPU time want to group these counts together and treat all three
* of them in parallel.
*/
struct task_cputime {
cputime_t utime;
cputime_t stime;
unsigned long long sum_exec_runtime;
};
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