Kazuo Ito <ito.kazuo@xxxxxxxxxxxxx> wrote: > Write throughput to LVM snapshot origin volume is an order > of magnitude slower than those to LV without snapshots or > snapshot target volumes, especially in the case of sequential > writes with O_SYNC on. > > The following patch originally written by Kevin Jamieson and > Jan Blunck and slightly modified for the current RCs by myself > tries to improve the performance by modifying the behaviour > of kcopyd, so that it pushes back an I/O job to the head of > the job queue instead of the tail as process_jobs() currently > does when it has to wait for free pages. This way, write > requests aren't shuffled to cause extra seeks. Did you check for starvation problems, too? -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
