The value after the process name ("31" in your trace snip) is the
number of requests flushed from the plug queue to the I/O queue during
the unplug.
To identify which inode a block belongs to you can try to use file
system specific utils: e.g., xfs_bmap for xfs, debugfs for ext2/3.
Also there are FIBMAP and FIEMAP ioctls that can help you. Another
ways is to instrument your file system's code to produce a trace/map
of blocks; well, if you have time for that ;)
HTH,
Vasily
On Wed, Mar 7, 2012 at 10:06 AM, Josh Hunt <joshhunt00@xxxxxxxxx> wrote:
> I am trying to debug a stall I am seeing with CFQ and in the
> blktrace/blkparse output I see unplugging lines like the following:
>
> 8,3 1 7809 1532.225997730 168 U N [sync_supers] 31
>
> My question is what does the value after the process name represent? I
> see this value increasing from 1, I believe, and then eventually the
> value appears to get reset.
>
> I was also wondering if it is possible to translate the block
> information provided in blktrace to the corresponding inode?
>
> Thanks for your help!
> Josh
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