From: Dan Smith <danms@xxxxxxxxxx> Subject: Thoughts on removing the remap cache Date: Fri, 29 Sep 2006 14:36:58 -0700 > However, all of my tests up until now have been with dbench. I think > that dbench works well in cases where latency is high, which is of > course the case since we're sending all requests to userspace. When I > try to boot a Xen domU with root on dm-userspace (without the > caching), it is *painfully* slow. I assume this is because the domU > boot is doing a lot of synchronous, sequential operations. > > Since domU performance was good when I was caching mappings in the > kernel, I would assume that the difference in performance is related > to the caching. I guess that dbench generates relatively large size I/Os than common workloads, which is more sensitive to latency. Seems that Xen camp is pretty happy with blktap. So dm-userspace should be ok with domU. Maybe it's time to try ring buffer stuff again. :) Ok, I'll salvage and update the old patch, post a new patch compatible with the current code. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
