On 6/20/12 12:18 AM, Norbert Preining wrote: > Hi Eric, > > On Di, 19 Jun 2012, Eric Sandeen wrote: >> blktrace of the actions would show you something interesting as well. > > I tried to understand the output, but didn't get any information > that tells me something. > > I rebooted into single user mode, started blktrace on sda, then run > time ls -l /..../dir/with/links/ >/dev/null, stopped the blktrace. > > Then I run blkparse and btt etc to generate a variety of data. ... > > I don't know if that shows anything of interest, but if you need more, > and want to waste a bit of time looking at the data, I have uploaded > everything created into > http://www.logic.at/people/preining/BlkParse.tar.gz Here are the overall stats: Total (sda): Reads Queued: 8,864, 35,456KiB Writes Queued: 90, 7,980KiB Read Dispatches: 8,864, 35,456KiB Write Dispatches: 49, 7,980KiB Reads Requeued: 0 Writes Requeued: 0 Reads Completed: 8,864, 35,456KiB Writes Completed: 59, 7,980KiB Read Merges: 0, 0KiB Write Merges: 41, 164KiB IO unplugs: 81 Timer unplugs: 0 so almost all reads, and no read merges; almost 35 megabytes read and every one was a small 4k IO. It's doing about 120 seeks/second. I'm a little surprised that there was no read merging... Let me think about this. :) -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
