On Tue, 6 Sep 2005 19:35:49 +0000 (UTC), Thomas Bellman <[EMAIL PROTECTED]> wrote:
>Michael Sparks <[EMAIL PROTECTED]> writes: > >> Similarly, from >> a unix command line perspective, the following will automatically take >> advantage of all the CPU's I have available: > >> (find |while read i; do md5sum $i; done|cut -b-32) 2>/dev/null |sort > >No, it won't. At the most, it will use four CPU:s for user code. > >Even so, the vast majority of CPU time in the above pipeline will >be spent in 'md5sum', but those calls will be run in series, not >in parallell. The very small CPU bursts used by 'find' and 'cut' >are negligable in comparison, and would likely fit within the >slots when 'md5sum' is waiting for I/O even on a single-CPU >system. > >And I'm fairly certain that 'sort' won't start spending CPU time >until it has collected all its input, so you won't gain much >there either. > Why wouldn't a large sequence sort be internally broken down into parallel sub-sequence sorts and merges that separate processors can work on? Regards, Bengt Richter -- http://mail.python.org/mailman/listinfo/python-list
