On Jul 11, 2011, at 8:07 PM, Andy Campbell wrote: > Hi ext4 mailing list members, > > I hope you can help me with a problem. > > I recently upgraded my main audio PC to Fedora FC15 and, at the same > time, reformatted by root drive to ext4. Since this upgrade this, my > system has high system latency which is causing my audio hardware > (firewire) to experience buffer under-runs (XRUNs). This causes > "unhandled xrun" errors and the audio software fails. What were you using before? ext3 ? It may be that ext4's default use of barriers (for safety reasons) is causing a difference. Try mounting your file systems with barrier=0. For the root filesystem, add "rootflags=barrier=0". This is an unsafe way to run, in that if you have a power failure while you are writing to the disk, your file system(s) could get corrupted. Ext3 defaulted to this for historical reasons (although the enterprise Linux systems, RHEL and SuSE changed the default for safety reasons). If this solves the problem, I'd suggest that you look into finding ways to increase the buffer size of your audio system (were you recording or doing playback at the time). You might also try to see if there was some amount of disk activity (especially write activity) that could be avoided or find some way of avoiding the use of fsync() so that you can re-enable write barriers without causing your latency skips. Regards, -- Ted -- 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
