<div dir="ltr">endianness... in old vm float were stored in big endian, so converting one int->float is faster than reversing float endianness (as it is programmed in the vm at least)<br></div><div class="gmail_extra"><br>
<br><div class="gmail_quote">2013/9/28 Bob Arning <span dir="ltr"><<a href="mailto:arning315@comcast.net" target="_blank">arning315@comcast.net</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<font face="Georgia">FWIW, I reran my 3 tests and the gap in the 2
interpreter versions narrowed, but old is still faster. And I
still can't guess why a pure float compare is slower than a
float-int compare.<br>
<br>
Cheers,<br>
Bob<br>
<br>
Squeak3.2gamma(interp 3.8.12)<br>
1 < 1.0 = #(507 506 500)<br>
1.0 < 1.0 = #(764 776 768)<br>
1 < 1 = #(230 234 238)<br>
1.0 < 1 = #(501 503 496)<br>
<br>
Squeak4.5 (cog)<br>
1 < 1.0 = #(23562 28802 28797)<br>
1.0 < 1.0 = #(122 122 125)<br>
1 < 1 = #(87 91 90)<br>
1.0 < 1 = #(151 149 149)<br>
<br>
Squeak4.5(interp 5.7.4.1)<br>
1 < 1.0 = #(618 612 605)<br>
1.0 < 1.0 = #(845 845 856)<br>
1 < 1 = #(269 272 269)<br>
1.0 < 1 = #(586 581 591)<br>
<br>
<br>
</font><div class="im">
<div>On 9/27/13 9:08 PM, David T. Lewis
wrote:<br>
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<pre>On Fri, Sep 27, 2013 at 05:51:33PM -0400, Bob Arning wrote:
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<blockquote type="cite">
<pre>I thought I'd extend the test to an older squeak&vm
---interpreter vm (3.8.12) squeak 3.2 ---------
Float compareTiming: 1 to: 1.0 ==> 496
Float compareTiming: 1.0 to: 1.0 ==> 761
Float compareTiming: 1 to: 1 ==> 225
Float compareTiming: 1.0 to: 1 ==> 494
---interpreter vm (5.7.4.1) squeak 4.5 ---------
Float compareTiming: 1 to: 1.0 ==> 719
Float compareTiming: 1.0 to: 1.0 ==> 991
Float compareTiming: 1 to: 1 ==> 312
Float compareTiming: 1.0 to: 1 ==> 686
The old one wins.
Cheers,
Bob
</pre>
</blockquote>
<pre>(CC to vm-dev list)
I get different results on my Linux PC.
- Squeak 3.2 with interpreter VM compiled by Ian, circa 2006:
Float compareTiming: 1 to: 1.0 ==> 1041
Float compareTiming: 1.0 to: 1.0 ==> 1432
Float compareTiming: 1 to: 1 ==> 390
Float compareTiming: 1.0 to: 1 ==> 1108
- Squeak 4.4 with Ian's 4.4.7-2357 VM, circa 2012:
Float compareTiming: 1 to: 1.0 ==> 840
Float compareTiming: 1.0 to: 1.0 ==> 1176
Float compareTiming: 1 to: 1 ==> 420
Float compareTiming: 1.0 to: 1 ==> 836
- Squeak 4.4 with my locally compiled 4.12.6.2787 VM (because I cannot use
Ian's 4.10.2.2614 from <a href="http://squeakvm.org" target="_blank">squeakvm.org</a> due to a Linux glib compatibility
problem for the outdated Linux on my PC):
Float compareTiming: 1 to: 1.0 ==> 782
Float compareTiming: 1.0 to: 1.0 ==> 1077
Float compareTiming: 1 to: 1 ==> 461
Float compareTiming: 1.0 to: 1 ==> 789
Perhaps there are other factors on the Mac platform (compiler changes,
etc) that are affecting the performance. Could you try Squeak 4.4 with
Ian's unix Mac VM from <a href="http://squeakvm.org" target="_blank">squeakvm.org</a> and see if you get different results?
<a href="http://squeakvm.org/unix/release/Squeak-4.10.2.2614-darwin10.8.0_i386.tar.gz" target="_blank">http://squeakvm.org/unix/release/Squeak-4.10.2.2614-darwin10.8.0_i386.tar.gz</a>
Dave
</pre>
<blockquote type="cite">
<pre>On 9/27/13 2:12 PM, Bob Arning wrote:
</pre>
<blockquote type="cite">
<pre>Following up Herbert's question, I wrote:
compareTiming: a to: b
"
---interpreter vm (5.7.4.1) ---------
Float compareTiming: 1 to: 1.0 ==> 719
Float compareTiming: 1.0 to: 1.0 ==> 991
Float compareTiming: 1 to: 1 ==> 312
Float compareTiming: 1.0 to: 1 ==> 686
---cog vm (2749)---------
*Float compareTiming: 1 to: 1.0 ==> 28162*
Float compareTiming: 1.0 to: 1.0 ==> 148
Float compareTiming: 1 to: 1 ==> 97
Float compareTiming: 1.0 to: 1 ==> 179
"
^[1000000 timesRepeat: [
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
a < b.
]] timeToRun
So, some obvious questions:
- in the interpreter vm, why is comparing two floats slower that an
integer and a float?
- what's up with Cog? Three tests are faster by the expected ratio and
one took a real dive.
Also, the profiler Herbert used could use some attention to the
NewFloat printing:
99.9 (898,069) Multiline1 doOneStep:
*77.30000000000001* (694,902) Multiline1 [HkTestLine] doTests:
73.8 (663,438) HkRunin [HkTestStation] canStartNextTest:
Cheers,
Bob
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