Messages in this thread | | | Date | Mon, 20 May 2002 16:33:40 +0530 | From | Manik Raina <> | Subject | Re: [PATCH]: adding counters to count bytes read/written |
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Thanks for the comments Matti, Please see inline ...
Matti Aarnio wrote: > > On Mon, May 20, 2002 at 03:09:36PM +0530, Manik Raina wrote: > > Hi Linus, > > > > This patch adds 2 counters to the task_struct for > > counting how many bytes were read/written using > > the read()/write() system calls. > > > > These counters may be useful in determining how > > many IO requests are made by each process. > > These are defined as UINTegers, are you sure that is appropriate type ? > What to do when they will overflow ? For short term activity tracking > they may be ok (4GB/200 MB/sec = 20 sec to wrap around), but for accounting > the overflow might not be liked thing..
How about 64 bit counters ? i feel those should go on without wraparound for a _very_ long time.
Did you have anything else in mind ?
> > For short-term IO-activity tracking they may indeed make sense, but I > would add another pair of counters to assist on that tracking. Namely > "values at the end of previous interval", which are maintained by the > activity tracking code.
Would this still be required if the counters are 64 bit ?
> > Reading one byte at the time won't grow those counters very fast, but will > cause massive amounts of syscalls, and context switches, so tracking data > amount alone isn't good enough.
What else would you suggest i track ? thanks Manik
> > .... > > diff -u -r ../temp/linux-2.5.12/include/linux/sched.h ./include/linux/sched.h > > --- ../temp/linux-2.5.12/include/linux/sched.h Wed May 1 05:38:47 2002 > > +++ ./include/linux/sched.h Mon May 20 09:25:32 2002 > > @@ -315,6 +315,7 @@ > > int link_count, total_link_count; > > struct tty_struct *tty; /* NULL if no tty */ > > unsigned int locks; /* How many file locks are being held */ > > + unsigned int bytes_written, bytes_read; > > /* ipc stuff */ > > struct sysv_sem sysvsem; > > /* CPU-specific state of this task */ > > /Matti Aarnio - 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/
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