Ariels wrote:
How can you
have 70% CPU idle and load average 1.25?
Load average is the average number of processes waiting for a
resource before they can continue running. CPU isn't the only
resource: your load can spike if your processes are hammering IO as well.
My guess is that, assuming your per-line transformations are relatively
small, this problem is disk-bound. If that's the case, buffering would
help. But there's only one sure way to find out: make some changes and see
if it makes a difference.
One possible scenario is: you have autoflush turned on on your input and/or output
filehandles. Every time you read a line, the disk heads travel to one end of
the disk. Every time you write a line, the disk heads travel all
the way back to the other end of the disk. This isn't unthinkable if your files are
large, or if your disk is full or fragmented. With more buffering, you'd decrease the
number of disk accesses, and decrease the overhead associated with
cross-disk head movement.
Just a guess, but possibly worth checking out.
Alan
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