On Wed, Nov 13, 2013 at 04:13:43PM +0000, Mears, Morgan wrote: > On Mon, Nov 04, 2013 at 12:22:26PM -0500, Krishnasamy, Somasundaram wrote: > > Mike, > > > > I was doing some testing with latest dm-cache code (from 'for-next' branch). I > > am having difficulty in making the cache to warm-up. I used the below script > > to read range of blocks repeatedly to get them promoted. I assume after > > reading a block for mq->promote_threshold + 4 times, a block will be > > promoted. But it is not happening. I also tested the same with the > > sequential_threshold set to very high value. > > > > Cache warming-up was relatively easier in the previous dm-cache code. Is this > > something you have seen in your testing?. Is there anything different should I > > do? > > I'm also testing with the for-next branch of linux-dm.git and seeing the > same thing as Somu. It's easy to reproduce; reading the same block on the > cached device over and over with dd does not result in that block being > promoted. > > I did notice that the "read miss" counter for the cached device increments > each time I execute dd, which I believe means this isn't a buffer cache > issue (I also used dd iflag=direct). The migration_threshold value > shouldn't be an issue for this test, but I set it to a very high value > anyway; didn't make any difference. > > Are there any tests in device-mapper-test-suite that you would recommend > for testing whether promotions are occurring as expected? > > --Morgan Hi Morgan, I just added these tests, promotion is occuring, just not as much as I'd like: https://github.com/jthornber/device-mapper-test-suite/blob/master/lib/dmtest/tests/cache/promotion_tests.rb Ah, these tests all trigger promotion via a write, I'll do some that just read. - Joe -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
