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Please don't use Uresource.struct_rusage in Modula-3.<BR>
I removed it. It is a portabilty/maintenance problem.<BR>
<BR>
- Jay<BR><BR> <BR>
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Date: Mon, 14 Mar 2011 23:21:49 +0000<BR>From: dabenavidesd@yahoo.es<BR>To: rcolebur@scires.com; m3devel@elegosoft.com; jay.krell@cornell.edu<BR>Subject: Re: [M3devel] question on use of Time.Now in thread test program<BR><BR>
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<TD vAlign=top>Hi all:<BR>see at:<BR>http://www.ic.unicamp.br/~stolfi/EXPORT/software/m3/Misc.html <BR><BR>CPUTime module.<BR>Thanks in advance<BR><BR>--- El <B>lun, 14/3/11, Jay K <I><jay.krell@cornell.edu></I></B> escribió:<BR>
<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px"><BR>De: Jay K <jay.krell@cornell.edu><BR>Asunto: Re: [M3devel] question on use of Time.Now in thread test program<BR>Para: rcolebur@scires.com, "m3devel" <m3devel@elegosoft.com><BR>Fecha: lunes, 14 de marzo, 2011 18:07<BR><BR>
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Time.Now() is very cheap on Windows and should cause no concern.<BR>It is just GetSystemTimeAsFileTime, which just reads some globals, followed by a simple unit and integer to double conversion.<BR>I would avoid 64bit Windows for now, very unfortunate, but I don't trust GetThreadContext.<BR> <BR> <BR>PROCEDURE Now(): T=<BR> VAR<BR> fileTime: WinBase.FILETIME;<BR> BEGIN<BR> WinBase.GetSystemTimeAsFileTime(fileTime);<BR> RETURN TimeWin32.FromFileTime(fileTime);<BR> END Now;<BR><BR><BR>double<BR>__cdecl<BR>TimeWin32__FromFileTime(FILETIME ft)<BR>{<BR> LARGE_INTEGER li;<BR><BR> li.LowPart = ft.dwLowDateTime;<BR> li.HighPart = ft.dwHighDateTime;<BR> return ((double)li.QuadPart) / 1.0e7;<BR>}<BR><BR><BR>Hm -- I don't like passing structs by value, too hard to be sure how it works -- I'd like to change this to be "READONLY" -- passed by pointer.<BR>Maybe code the entire thing in Modula-3 -- or more likely, the entire thing in C.<BR> <BR>Time.Now() might be more expensive on other platform, I don't know.<BR> <BR>I also see some failures, some success, no pattern.<BR>I think the success is just luck and the code is by its nature very non-deterministic.<BR> <BR> - Jay<BR> <BR>
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From: rcolebur@SCIRES.COM<BR>To: m3devel@elegosoft.com<BR>Date: Mon, 14 Mar 2011 18:45:44 -0400<BR>Subject: [M3devel] question on use of Time.Now in thread test program<BR><BR>
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<P class=ecxyiv1082952660ecxMsoNormal>I have a question/concern regarding Mika’s thread test program.</P>
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<P class=ecxyiv1082952660ecxMsoNormal>Each of the threads makes use of the Time.Now() call during each iteration of the thread’s main loop. </P>
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<P class=ecxyiv1082952660ecxMsoNormal>I haven’t fully investigated, but does anyone have concern that so many calls to the system clock from multiple competing threads might have some side effect on the running of multiple threads?</P>
<P class=ecxyiv1082952660ecxMsoNormal> </P>
<P class=ecxyiv1082952660ecxMsoNormal>I’ve also done some limited experimentation with use of counters to see how many times each type of thread is able to go thru its loop between reporting intervals.</P>
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<P class=ecxyiv1082952660ecxMsoNormal>I continue to see various types of crashes on Windows 7 (64-bit), but sometimes tests are able to succeed. I haven’t found a repeatable pattern yet to the crashes, so I am still investigating, but just thought it worth asking the above question about use of Time.Now().</P>
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<P class=ecxyiv1082952660ecxMsoNormal>I will also try to experiment with Windows XP 32-bit and report back.</P>
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<P class=ecxyiv1082952660ecxMsoNormal>Regards,</P>
<P class=ecxyiv1082952660ecxMsoNormal>Randy Coleburn</P></DIV></DIV></BLOCKQUOTE></TD></TR></TBODY></TABLE><BR> </body>
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