Re^3: Time::HiRes sleep does not always work

Could you post the output from the following on one machine that gives good results and one that gives bad:

#! perl -slw
use strict;
use Time::HiRes qw[ gettimeofday time ];

use Win32::API::Prototype;

ApiLink( 'kernel32', q[
    BOOL QueryPerformanceCounter( LARGE_INTEGER *lpPerformanceCount )
]) or die $^E;

ApiLink( 'kernel32', q[
    BOOL QueryPerformanceFrequency( LARGE_INTEGER *lpPerformanceCount 
+)
]) or die $^E;

sub int64_to_NV {
    my( $lo, $hi ) = unpack 'VV', $_[ 0 ];
    return $hi * 2**32 + $lo;
}

my $frequency = ' ' x 10;
QueryPerformanceFrequency( $frequency ) or die $^E;

print 'Counter changes ', int64_to_NV( $frequency ), ' times/second';

for ( 1 .. 10 ) {
    QueryPerformanceCounter( $frequency )or die $^E;
    print 'QPC: ',int64_to_NV( $frequency );
}


printf "GToD: %.8f\n", scalar gettimeofday() for 1 .. 10;
printf "Time: %.8f\n", time() for 1 .. 10;
[download]

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

Comment on Re^3: Time::HiRes sleep does not always work Download Code

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Re^4: Time::HiRes sleep does not always work by tone (Novice) on Aug 19, 2008 at 13:05 UTC
If I run your script on my machine (bad) I get: Counter changes 3579545 times/second QPC: 35752003971 QPC: 35752004170 QPC: 35752004356 QPC: 35752004527 QPC: 35752004695 QPC: 35752004854 QPC: 35752005017 QPC: 35752005169 QPC: 35752005333 QPC: 35752005487 GToD: 1219149309.90625000 GToD: 1219149309.90625000 GToD: 1219149309.90625000 GToD: 1219149309.90625000 GToD: 1219149309.90625000 GToD: 1219149309.90625000 GToD: 1219149309.90625000 GToD: 1219149309.90625000 GToD: 1219149309.90625000 GToD: 1219149309.90625000 Time: 1219149309.90625000 Time: 1219149309.90625000 Time: 1219149309.90625000 Time: 1219149309.90625000 Time: 1219149309.90625000 Time: 1219149309.90625000 Time: 1219149309.90625000 Time: 1219149309.90625000 Time: 1219149309.90625000 Time: 1219149309.90625000 [download] And here is the output from a "good" machine: Counter changes 3579545 times/second QPC: 76031246430 QPC: 76031246657 QPC: 76031246790 QPC: 76031247127 QPC: 76031247273 QPC: 76031247479 QPC: 76031247686 QPC: 76031247838 QPC: 76031247972 QPC: 76031248165 GToD: 1219150762.25000000 GToD: 1219150762.25004410 GToD: 1219150762.25007610 GToD: 1219150762.25010900 GToD: 1219150762.25013900 GToD: 1219150762.25017500 GToD: 1219150762.25020500 GToD: 1219150762.25024100 GToD: 1219150762.25027490 GToD: 1219150762.25030590 Time: 1219150762.25033810 Time: 1219150762.25036690 Time: 1219150762.25039600 Time: 1219150762.25042800 Time: 1219150762.25047900 Time: 1219150762.25053190 Time: 1219150762.25058200 Time: 1219150762.25063110 Time: 1219150762.25066710 Time: 1219150762.25069900 [download]	[reply] [d/l] [select]
Re^5: Time::HiRes sleep does not always work by BrowserUk (Patriarch) on Aug 19, 2008 at 13:28 UTC
It's not your hardware! Your machine is equally capable of high resolution as the "good" machine. That's identified by the first line: `Counter changes 3579545 times/second` which displays the granularity of the timer, which is the same on both machines. That means if they are both using the same version of Time::HiRes, then they should be giving the same results. The first thing I would try is re-installing the module. From CPAN if you are compiler-capable. From a PPM otherwise. And, if your paranoid like me, you'll blow away the existing files first: `<yourperl>/lib/Time::HiRes.pm <yourperl>/lib/auto/Time/HiRes/*` [download] If the problem persists after that, something very hookey is going on with your install. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l] [select]
Re^6: Time::HiRes sleep does not always work by tone (Novice) on Aug 20, 2008 at 08:13 UTC
The "Good" machine that I tried above wasn't the original one that my testing was done on because that colleague wasn't at work yesterday but I got to run the test today and the results from that test are below Counter changes 14318180 times/second QPC: 4512760987142 QPC: 4512760987382 QPC: 4512760987508 QPC: 4512760987617 QPC: 4512760987726 QPC: 4512760987835 QPC: 4512760987939 QPC: 4512760988043 QPC: 4512760988148 QPC: 4512760988253 GToD: 1219217113.05580000 GToD: 1219217113.05580000 GToD: 1219217113.05580000 GToD: 1219217113.05580000 GToD: 1219217113.05580000 GToD: 1219217113.05580000 GToD: 1219217113.05580000 GToD: 1219217113.05580000 GToD: 1219217113.05580000 GToD: 1219217113.05580000 Time: 1219217113.05580000 Time: 1219217113.05580000 Time: 1219217113.05580000 Time: 1219217113.05580000 Time: 1219217113.05580000 Time: 1219217113.05580000 Time: 1219217113.05580000 Time: 1219217113.05580000 Time: 1219217113.05580000 Time: 1219217113.05580000 [download] I'm going to try and reinstall my Time::HiRes anyway to to make sure the problem isn't there	[reply] [d/l]
Re^7: Time::HiRes sleep does not always work by BrowserUk (Patriarch) on Aug 20, 2008 at 08:53 UTC
Re^8: Time::HiRes sleep does not always work by tone (Novice) on Aug 20, 2008 at 13:29 UTC