http://bugzilla.suse.com/show_bug.cgi?id=1030310 Bug ID: 1030310 Summary: Regression in WAL and COMMIT times for pgioperf-bench on ext3 Classification: openSUSE Product: openSUSE Tumbleweed Version: Current Hardware: Other OS: Other Status: NEW Severity: Normal Priority: P5 - None Component: Kernel Assignee: kernel-maintainers@forge.provo.novell.com Reporter: jack@suse.com QA Contact: qa-bugs@suse.de Found By: --- Blocker: --- Commit 06bd3c36a733ac27962fea7d6f47168841376824 "ext4: fix data exposure after a crash" regressed WAL times of pgioperf-bench on ext3 filesystem ~100x for balada.arch.suse.de. COMMIT times regressed ~10x. The benchmark is doing random 8k writes into a large datafile (2*memsize) calling fsync after 800MB written and cycling 8k writes into wal file, fsyncing it every 5 writes. In parallel there are lots of random reads going on. The regression is caused by the fact that before above mentioned commit datafile inode was always attached to transaction in ext4_write_end() and thus random writes were continuously trickled to the filesystem using WRITE_SYNC writes. After the patch this does not happen and writes are written back by flush worker using async writes. Likely these get starved by parallel readers and as a result WAL writer gets stuck in write(2) for extended periods of time. -- You are receiving this mail because: You are on the CC list for the bug.