Messages in this thread |  | | From | (Marlys Kohnke) | Subject | blocks read/written counters | Date | Mon, 13 Nov 2000 14:31:37 -0600 |
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As part of the new resource counters I'm adding for our job accounting feature, I'm trying to gather blocks read and written on a per task basis (which will get rolled into a per job statistic outside of the kernel). I added task struct counters which get incremented in drivers/block/ll_rw_blk.c in the drive_stat_acct() procedure, which is where the kernel stats are gathered for blocks read/written.
What I noticed, though, was that some system daemons would be the current task when going through drive_stat_acct() for writes, but usually it was kupdate. In doing some searching, I now see that kupdate is the kernel thread responsible to flush the dirty buffers out to disk. I need to capture this blocks read/written information for user processes, not kupdate.
We were able to get this block info on the Cray systems (which have separate direct IO and buffered IO) and somewhat on the IRIX systems (where whichever process is running when the buffers get flushed is the process which gets charged for those buffers). Apparently, this information is useful for capacity planning and in cache thrashing situations. It's not used for billing purposes.
Is there a reasonable way on Linux to get any blocks read and written information on a per task basis? Thanks for any help.
---- Marlys Kohnke Silicon Graphics Inc. kohnke@sgi.com 655F Lone Oak Drive (651)683-5324 Eagan, MN 55121 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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