On Sun, Jan 23, 2011 at 11:25:26AM +0100, Tejun Heo wrote: > Again, issuing flushes as fast as possible isn't necessarily better. > It might feel counter-intuitive but it generally makes sense to delay > flush if there are a lot of concurrent flush activities going on. > Another related interesting point is that with flush merging, > depending on workload, there's a likelihood that FUA, even if the > device supports it, might result in worse performance than merged DATA > + single POSTFLUSH sequence. Let me add a bit. In general, I'm a bit skeptical about the usefulness of hardware FUA on a rotating disk. All it saves is a single command issue overhead. On storage array or SSDs, the balance might be different tho. Event hen, with flush merging, I think it would heavily depend on the workload which way it would turn out. Thanks. -- tejun -- 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
