CODEWITHSUNDEEP
multithreadingperlprofiling
Wolfgang
Wolfgang

Reputation: 254

Perl threads get iterations speed

I have some code:

for my $t (1..$threads) {
  push @threads, threads->create(\&action_, $t);
}
for my $t (@threads) {
  $t->join();
}

sub action_ {
  while (@sites) {
    my $url = shift @sites;
    for my $data1 (@data) {
      for my $data2 (@data2) {
        something($url, $data1, $data2);
      }
    }
  }
}

How to get speed(number of calls method "something") per second(or minute)? Thanks.

Upvotes: 1

Views: 93

Answers (2)

pilcrow
pilcrow

Reputation: 58731

If you're looking to do it yourself quickly, a gross estimate can be obtained like so:

use List::Util qw(sum);
use feature qw(say);
...

my $t0 = time();  # See also Time::HiRes
threads->create(\&action_) for 1 .. $nthreads;
my $nsomething = sum map { $_->join } threads->list();
my $elapsed = time() - $t0;

say "Among $nthreads threads we called something() ",
    ($nsomething/$elapsed),
    " times per second";

sub action_ {
  my $n;
  while (...) { ... something(); $n++; ... }
  return $n;
}

If that's not fine enough, you might have each call to something() push the time it was invoked on to a threads::shared::share()d array — or in a thread-local array that you collect after the join(), or printed to a mutex-protected filehandle or whatever. Then you can do whatever you like with the time series you've generated.

Upvotes: 2

RichM
RichM

Reputation: 272

Perl has a number of benchmarking modules in CPAN. Take a look at: http://perldoc.perl.org/Benchmark.html

This explains it well; basically the code you want to benchmark is wrapped up in a subroutine and you're free to count or compare different routines.

The method I use most commonly is under the heading 'Methods' and 'New'.

Upvotes: 2

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