Re^3: Standard way to convert timezone in multithreaded script

perl -Mthreads -e'$n=3;for (1..$n){$t[$_]=threads->create(sub{my $r; while(1){$r++}});}; sleep 10;threads->exit()'

FWIW, I can attest that setting n=2 pegs both cores on my amd 3800+ running Arch Linux. However, n=1 (recommended setting) only pegs one core.

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Re^4: Standard way to convert timezone in multithreaded script by tirwhan (Abbot) on Nov 24, 2009 at 18:23 UTC
However, n=1 (recommended setting) only pegs one core. Yes, of course. A single thread will only execute on one core. Which core that is may change (it's up to the OS), but it won't run on more than one core simultaneously. Multiple threads will. (I guess you already know this, just saying it explicitly in case someone reads all of this and is under the impression that simply saying "use threads;" will make a program run concurrently on several CPUs. That would be magic, not concurrency :-) All dogma is stupid.	[reply] [d/l]

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Re^4: Standard way to convert timezone in multithreaded script
by tirwhan (Abbot) on Nov 24, 2009 at 18:23 UTC

However, n=1 (recommended setting) only pegs one core.

Yes, of course. A single thread will only execute on one core. Which core that is may change (it's up to the OS), but it won't run on more than one core simultaneously. Multiple threads will.

(I guess you already know this, just saying it explicitly in case someone reads all of this and is under the impression that simply saying "use threads;" will make a program run concurrently on several CPUs. That would be magic, not concurrency :-)

All dogma is stupid.

[reply]
[d/l]