Messages in this thread | | | Date | Fri, 9 Jun 2006 04:21:29 -0700 | From | Andrew Morton <> | Subject | Re: [Patch][RFC] Disabling per-tgid stats on task exit in taskstats |
| |
On Fri, 09 Jun 2006 16:21:46 +0530 Balbir Singh <balbir@in.ibm.com> wrote:
> Andrew Morton wrote: > > On Fri, 09 Jun 2006 03:41:04 -0400 > > Shailabh Nagar <nagar@watson.ibm.com> wrote: > > > > > >>Hence, this patch introduces a configuration parameter > >> /sys/kernel/taskstats_tgid_exit > >>through which a privileged user can turn on/off sending of per-tgid stats on > >>task exit. > > > > > > That seems a bit clumsy. What happens if one consumer wants the per-tgid > > stats and another does not? > > For all subsystems that re-use the taskstats structure from the exit path, > we have the issue that you mentioned. Thats because several statistics co-exist > in the same structure. These subsystems can keep their tgid-stats empty by not > filling up anything in fill_tgid() or using this patch to selectively enable/disable > tgid stats. > > For other subsystems, they could pass tgidstats as NULL to taskstats_exit_send(). >
I don't understand. If a subsystem exists then it fills in its slots in the taskstats structure, doesn't it?
No other subsystem needs a global knob, does it?
You see the problem - if one userspace package wants the tgid-stats and another concurrently-running one does now, what do we do? Just leave it enabled and run a bit slower?
If so, how much slower? Your changelog says some potential users don't need the tgid-stats, but so what? I assume this patch is a performance thing? If so, has it been quantified?
- 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/
| |