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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>No, not really. One way you could test
would be to see how normal Spread reacts when you jump the clock around and
then contrast that with how it operates using your monotonic clock.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p><font size=2 color=navy face="Times New Roman"><span style='font-size:10.0pt;
color:navy'>Cheers!<br>
<br>
---<br>
John Lane Schultz<br>
Spread Concepts LLC<br>
Phn: 443 838 2200 </span></font><o:p></o:p></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
drago.krznaric@se.transport.bombardier.com
[mailto:drago.krznaric@se.transport.bombardier.com] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Monday, May 11, 2009 4:18 AM<br>
<b><span style='font-weight:bold'>To:</span></b> John Schultz<br>
<b><span style='font-weight:bold'>Cc:</span></b> <st1:PersonName w:st="on">spread-users@lists.spread.org</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Spread-users] Should
I dare touch the clock?</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><br>
</span></font><font size=2 face="Microsoft Sans Serif"><span style='font-size:
10.0pt;font-family:"Microsoft Sans Serif"'>Thanky you for prompt reply.
If I would like to try to use the monotonic clock, do you know if there</span></font>
<br>
<font size=2 face="Microsoft Sans Serif"><span style='font-size:10.0pt;
font-family:"Microsoft Sans Serif"'>is some test suite I could use to see that
things work after the change?<br>
</span></font><font size=1 face="Microsoft Sans Serif"><span
style='font-size:7.5pt;font-family:"Microsoft Sans Serif"'><br>
Please consider the environment before you print / Merci de penser à
l'environnement avant d'imprimer / Tänk på miljön innan du skriver ut </span></font><br>
<br>
<o:p></o:p></p>
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<br>
<br>
</span></font><b><font size=1 face=sans-serif><span style='font-size:7.5pt;
font-family:sans-serif;font-weight:bold'>John Schultz
<jschultz@spreadconcepts.com></span></font></b> <br>
<font size=1 face=sans-serif><span style='font-size:7.5pt;font-family:sans-serif'>2009-05-08
17:50</span></font> <o:p></o:p></p>
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<p class=MsoNormal align=right style='text-align:right'><font size=1
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<p class=MsoNormal><font size=1 face=sans-serif><span style='font-size:
7.5pt;font-family:sans-serif'>Drago
Krznaric/SE/Transport/Bombardier@TRANSPORT</span></font> <o:p></o:p></p>
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<p class=MsoNormal align=right style='text-align:right'><font size=1
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<p class=MsoNormal><st1:PersonName w:st="on"><font size=1 face=sans-serif><span
style='font-size:7.5pt;font-family:sans-serif'>spread-users@lists.spread.org</span></font></st1:PersonName>
<o:p></o:p></p>
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<p class=MsoNormal align=right style='text-align:right'><font size=1
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<p class=MsoNormal><font size=1 face=sans-serif><span style='font-size:
7.5pt;font-family:sans-serif'>Re: [Spread-users] Should I dare touch the
clock?</span></font><o:p></o:p></p>
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<br>
<br>
<br>
</span></font><font size=1 face="Courier New"><span style='font-size:7.5pt;
font-family:"Courier New"'>Spread currently uses the wall clock time for all of
its time based calculations. If you only move the clock a little, then
you probably won't have any issues, although I'm not 100% sure. If you
drastically jump the clock forward, then I can see major issues as suddenly the
already scheduled timeouts will take forever to fire. If you drastically
jump the clock backwards, then a lot of timeouts will fire prematurely, which
might cause a spurious partition or something, but the system would probably
then return to normal operations immediately thereafter.</span></font> <br>
<br>
<font size=1 face="Courier New"><span style='font-size:7.5pt;font-family:"Courier New"'>The
events system definitely should be moved over to using a monotonic clock on
whatever platforms such a service is available. We would like to do this
sometime in the future, but if you experiment with it and get something to work
and want to contribute it back, then that would be great.</span></font> <br>
<br>
<font size=1 face="Courier New"><span style='font-size:7.5pt;font-family:"Courier New"'>Cheers!</span></font>
<br>
<font size=1 face="Courier New"><span style='font-size:7.5pt;font-family:"Courier New"'>John</span></font>
<br>
<br>
<font size=1 face="Courier New"><span style='font-size:7.5pt;font-family:"Courier New"'>---</span></font>
<br>
<font size=1 face="Courier New"><span style='font-size:7.5pt;font-family:"Courier New"'>John
Lane Schultz</span></font> <br>
<font size=1 face="Courier New"><span style='font-size:7.5pt;font-family:"Courier New"'>Spread
Concepts LLC</span></font> <br>
<font size=1 face="Courier New"><span style='font-size:7.5pt;font-family:"Courier New"'>Phn:
443 838 2200 </span></font><br>
<font size=1 face="Courier New"><span style='font-size:7.5pt;font-family:"Courier New"'>Fax:
301 560 8875</span></font> <br>
<br>
<font size=1 face="Courier New"><span style='font-size:7.5pt;font-family:"Courier New"'>Friday,
May 8, 2009, 11:19:23 AM, you wrote:</span></font> <o:p></o:p></p>
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</span></font><font size=1 face=Tahoma><span style='font-size:7.5pt;
font-family:Tahoma'>Hi,</span></font><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'> </span></font><br>
<br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>I
have a single spread daemon and a bunch of programs communicating via spread
messages </span></font><br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>through
this daemon. All programs and the daemon are running on the same machine.</span></font><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> </span></font><br>
<br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>From
previous mails on this list, I know that people have had problems with
message </span></font><br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>delivery
when they have changed the clock, via settimeofday and even NTP.</span></font><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> </span></font><br>
<br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>But
I'm not sure if this can only occur when there are multiple daemons or if it
can happen</span></font><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma'> </span></font><br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>in
my case too. Browsing through the code in events.c, it looks as it could
happen in my case </span></font><br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>too,
although the probability is perhaps small.</span></font><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> </span></font><br>
<br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>Has
someone a testprogram/argument proving that this is either true or false?</span></font><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> </span></font><br>
<br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>I'm
thinking about changing the gettimeofday call in E_get_time to something that
is not</span></font><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma'> </span></font><br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>affected
by some external source setting the time, for example,
clock_gettime(CLOCK_MONOTONIC).</span></font><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'> </span></font><br>
<br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>Has
someone done something similar before?</span></font><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'> </span></font><br>
<br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>Cheers,</span></font><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> </span></font><br>
<font size=1 face=Tahoma><span style='font-size:7.5pt;font-family:Tahoma'>Drago
</span></font><o:p></o:p></p>
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<br>
<br>
<br>
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