Posted Sep 2, 2010 6:09 UTC (Thu) by giraffedata
In reply to: sreadahead
Parent article: LinuxCon: A tale of two bootcharts
That's the whole point. The HD is doing a lot of seeking when it could just be moving the head down the platter across all of the tracks linearly, which means zero seek time.
That's the whole point of what? It wasn't the point of the article or any previous comment, since they talked about SSDs (no seek time) and about CPU overlapping disk time. (Simply overlapping CPU and disk time, on mechanical disk systems I know would be barely noticeable, because the disk time is so great compared to the CPU time).
On the SSD-based system, though, the overlap is significant because the disk time is so much shorter. If overlapping buys you 7 seconds toward a 10 second boot, the CPU time and disk time must be of the same order.
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