Message-ID: <44D24500.7060107@sgi.com>
Date: Thu, 03 Aug 2006 11:48:32 -0700
From: Jay Lan <jlan@sgi.com>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040906
MIME-Version: 1.0
To: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Andrew Morton <akpm@osdl.org>, Jay Lan <jlan@engr.sgi.com>,
       linux-kernel@vger.kernel.org, balbir@in.ibm.com, jes@sgi.com,
       csturtiv@sgi.com, tee@sgi.com, guillaume.thouvenin@bull.net
Subject: Re: [patch 1/3] basic accounting over taskstats
References: <44D179A5.4000606@engr.sgi.com> <20060802235219.25a072e7.akpm@osdl.org> <44D20079.2000601@watson.ibm.com>
In-Reply-To: <44D20079.2000601@watson.ibm.com>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1787
Lines: 52

Shailabh Nagar wrote:
> Andrew Morton wrote:
> 
>>
>> Or we remove this field altogether, perhaps.  The same info is available
>> from /proc/pid/stat anyway.  Is it really needed?
>>
> 
> Gathering this data in userspace from /proc might be
> difficult esp. for short-lived tasks.

This is a serious concern. I think increasing TS_COMM_LEN
to 32 would be a good solution.

> 
> Also, /proc may not be mounted ? I'd heard somewhere that
> some sysadmins don't install /proc for security reasons.
> Don't know how far thats true.
> 
> Several other fields, totalling 58 bytes, added by the CSA
> patches are also duplicated in /proc/pid/stat. But all of them
> could change in value during the lifetime of a task so I'm
> guessing its not useful to get them from /proc
> even if some kind of userspace polling of the value was
> possible.

The same concern above applies to here, doesn't it?

Regards,
  - jay


> 
> But if there is a way, it would sure save a lot of payload
> sent over taskstats !
> 
> "duplicate" fields from CSA:
> +    __u8    ac_nice;        /* task_nice */
> +    char    ac_comm[TS_COMM_LEN];    /* Command name */
> +    __u8    ac_sched;        /* Scheduling discipline */
> +    __u32    ac_pid;            /* Process ID */
> +    __u32    ac_ppid;        /* Parent process ID */
> +    __u64    ac_utime;        /* User CPU time [usec] */
> +    __u64    ac_stime;        /* SYstem CPU time [usec] */
> +    __u64    ac_minflt;        /* Minor Page Fault */
> +    __u64    ac_majflt;        /* Major Page Fault */

-
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/