>Its possible that by doing larger >IOs we save CPU and use that CPU to push more data ?
This is absolutely right; my mistake -- the relevant number is CPU seconds per megabyte moved, not CPU seconds per elapsed second. But I don't think we're close enough to 100% CPU utilization that this explains much. In fact, the curious thing here is that neither the disk nor the CPU seems to be a bottleneck in the slow case. Maybe there's some serialization I'm not seeing that makes less parallelism between I/O and execution. Is this a single thread doing writes and syncs to a single file? -- Bryan Henderson IBM Almaden Research Center San Jose CA Filesystems - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
