How to use high-resolution gettimeofday in Perl

Last updated on June 2, 2020 by Dan Nanni

In some cases, you may need to measure time in high-resolution, for example, microsecond resolution as provided by gettimeofday() system call. In order to use microsecond-resolution time in Perl, you can use Time::HiRes Perl module. This module provides microsecond-resolution "wall-clock" time.

Starting with Perl v5.8, Time::HiRes module comes as standard. If your Linux system does not have Time::HiRes, you can install it using CPAN as follows.

$ sudo perl -MCPAN -e ‘install Time::HiRes’

You can measure elapsed time in microsecond resolution with Time::HiRes as follows.

#/usr/bin/perl

use Time::HiRes qw( usleep ualarm gettimeofday tv_interval );

my $t0 = [gettimeofday];
[add some computation intensive routine]
my $elapsed = tv_interval ($t0, [gettimeofday]);

Alternatively, you can get second/microsecond components separately as follows.

# get current time
my ($seconds, $microseconds) = gettimeofday;

The Time::HighRes module supports up to microsecond granularity. High-level scripted languages such as Perl do not provide nanosecond-resolution timestamps. For that, you will need different languages such as C/C++.

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