lkml.org 
[lkml]   [2006]   [Aug]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch 1/3] add basic accounting fields to taskstats
Balbir Singh wrote:
> Jay Lan wrote:
>
>>
>> -#define TASKSTATS_VERSION 1
>> +#define TASKSTATS_VERSION 2
>> +#define TASK_COMM_LEN 16
>>
>
>
> We should find a way to keep this in sync with with the definition
> in linux/sched.h (won't we a warning if both this header and
> linux/sched.h are included together?)

I do not know how to sync it up. This header linux/taskstats.h is
meant to be included by userspace programs. If an application
happens to include linux/sched.h, which includes linux/time.h,
the application will very likely have compilation errors because
the "struct timespec" declaration in <linux/time.h> and <time.h>
are conflicting.

The <linux/acct.h> defines it to
#define ACCT_COMM 16

I can change our define to TS_COMM_LEN with remakes saying it
should be in sync with the TAKS_COMM_LEN defined in linux/sched.h.

If there is a better way, i am eager to know it.

>
>
>
>> + * fill in basic accounting fields
>> + */
>> +static void bacct_add_tsk(struct taskstats *stats, struct task_struct
>> *tsk)
>> +{
>> + u64 run_time;
>> + struct timespec uptime;
>> +
>> + /* calculate run_time in nsec */
>> + do_posix_clock_monotonic_gettime(&uptime);
>> + run_time = (u64)uptime.tv_sec*NSEC_PER_SEC + uptime.tv_nsec;
>> + run_time -= (u64)current->group_leader->start_time.tv_sec *
>> NSEC_PER_SEC
>> + + current->group_leader->start_time.tv_nsec;
>> + do_div(run_time, NSEC_PER_USEC); /* rebase run_time to usec */
>> + stats->ac_etime = run_time;
>> + do_div(run_time, USEC_PER_SEC); /* rebase run_time to sec */
>> + stats->ac_btime = xtime.tv_sec - run_time;
>> + if (thread_group_leader(tsk)) {
>> + stats->ac_exitcode = tsk->exit_code;
>> + if (tsk->flags & PF_FORKNOEXEC)
>> + stats->ac_flag |= AFORK;
>> + }
>> + if (tsk->flags & PF_SUPERPRIV)
>> + stats->ac_flag |= ASU;
>> + if (tsk->flags & PF_DUMPCORE)
>> + stats->ac_flag |= ACORE;
>> + if (tsk->flags & PF_SIGNALED)
>> + stats->ac_flag |= AXSIG;
>> + stats->ac_nice = task_nice(tsk);
>> + stats->ac_sched = tsk->policy;
>> + stats->ac_uid = tsk->uid;
>> + stats->ac_gid = tsk->gid;
>> + stats->ac_pid = tsk->pid;
>> + stats->ac_ppid = (tsk->parent) ? tsk->parent->pid : 0;
>> + stats->ac_utime = tsk->utime * USEC_PER_TICK;
>> + stats->ac_stime = tsk->stime * USEC_PER_TICK;
>
>
> I think you should use the portable cputime_xxxx() API since
> tsk->utime and tsk->stime are of type cputime_t

Will fix it.

>
>
>> + /* Each process gets a minimum of a half tick cpu time */
>> + if ((stats->ac_utime == 0) && (stats->ac_stime == 0)) {
>> + stats->ac_stime = USEC_PER_TICK/2;
>> + }
>> +
>
>
> This is confusing. Half tick does not make any sense from the
> scheduler view point (or am I missing something?), so why
> return half a tick to the user.

It must be inherited from old code dated back to Cray UNICOS.
I do not know if bad thing can happen if both utime and stime
are less than 1 usec... I guess not. But i agree that
half a tick does not make sense. To play safe, we can change
it to 1 usec if both utime and stime are sub microsecond.
What do you think?

Thanks,
- jay


>
>

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-08-01 23:55    [W:0.101 / U:0.488 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site