在 2017年03月07日 06:40, Andrew Morton 写道:
> On Fri, 3 Mar 2017 10:33:44 +0800 Zhang Xiao <[email protected]> wrote:
>
>> Add elapsed time, user CPU time and system CPU time to
>> thread group status request.
>>
>> --- a/kernel/taskstats.c
>> +++ b/kernel/taskstats.c
>> @@ -210,6 +210,7 @@ static int fill_stats_for_tgid(pid_t tgid, struct
>> taskstats *stats)
>> struct task_struct *tsk, *first;
>> unsigned long flags;
>> int rc = -ESRCH;
>> + u64 delta, utime, stime;
>>
>> /*
>> * Add additional stats from live tasks except zombie thread group
>> @@ -238,6 +239,16 @@ static int fill_stats_for_tgid(pid_t tgid, struct
>> taskstats *stats)
>> */
>> delayacct_add_tsk(stats, tsk);
>>
>> + /* calculate task elapsed time in nsec */
>> + delta = ktime_get_ns() - tsk->start_time;
>> + /* Convert to micro seconds */
>> + do_div(delta, NSEC_PER_USEC);
>> + stats->ac_etime += delta;
>> +
>> + task_cputime(tsk, &utime, &stime);
>> + stats->ac_utime += div_u64(utime, NSEC_PER_USEC);
>> + stats->ac_stime += div_u64(stime, NSEC_PER_USEC);
>> +
>> stats->nvcsw += tsk->nvcsw;
>> stats->nivcsw += tsk->nivcsw;
>> } while_each_thread(first, tsk);
>
> hm, OK, we were just leaving these at zero. Seems sane to me.
>
> It would be more efficient and perhaps more deterministic to sample
> ktime just once?
>
yes, that makes the code more readable. :-)
Thanks
Xiao
> --- a/kernel/taskstats.c~taskstats-add-e-u-stime-for-tgid-command-fix
> +++ a/kernel/taskstats.c
> @@ -211,6 +211,7 @@ static int fill_stats_for_tgid(pid_t tgi
> unsigned long flags;
> int rc = -ESRCH;
> u64 delta, utime, stime;
> + u64 start_time;
>
> /*
> * Add additional stats from live tasks except zombie thread group
> @@ -228,6 +229,7 @@ static int fill_stats_for_tgid(pid_t tgi
> memset(stats, 0, sizeof(*stats));
>
> tsk = first;
> + start_time = ktime_get_ns();
> do {
> if (tsk->exit_state)
> continue;
> @@ -240,7 +242,7 @@ static int fill_stats_for_tgid(pid_t tgi
> delayacct_add_tsk(stats, tsk);
>
> /* calculate task elapsed time in nsec */
> - delta = ktime_get_ns() - tsk->start_time;
> + delta = start_time - tsk->start_time;
> /* Convert to micro seconds */
> do_div(delta, NSEC_PER_USEC);
> stats->ac_etime += delta;
> _
>
>
