<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On 5 Aug 2010, at 14:37, Amaury Pouly wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">That can be due to lots of things. Just consider this difference:<br>- Wall time: preception of time form the user. That is, if you run your program at time T and it ends at time T+D, then the wall time is D normally<br>- Processor time: time allocated on the processor, which can even be greater than the wall time if the program uses several processors (if you have two processors, you can in theory use 2*D processor time for a wall time of D).<br>
<br>I don't know how the times are computed but it could be related to these points. And perhaps the time needed to do all the initialisation and loading of the executable is counted somewhere.<br></blockquote><div><br></div><div>Yes but the difference between the 'time' utility and the internal timers is not constant, with '-fsyntax-only' the internal timers report lower numbers but with '-emit-llvm-bc' they report higher ones.</div><div><br></div><div>In general is 'time' utility the more reliable one ?</div><div><br></div><div>-Argiris</div><br><blockquote type="cite"><br clear="all">Amaury Pouly<br>
<br><br><div class="gmail_quote">2010/8/5 Argyrios Kyrtzidis <span dir="ltr"><<a href="mailto:kyrtzidis@apple.com">kyrtzidis@apple.com</a>></span><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div style="word-wrap: break-word;">Hi,<div><br></div><div>When I try '-ftime-report' the numbers differ from 'time', either higher or lower, e.g:</div><div><br></div><div><font face="Monaco" size="3"><span style="font-size: 11px;">> time clang -cc1 lib/VMCore/Dominators.cpp -Iinclude -Ilib/VMCore -D_DEBUG -D_GNU_SOURCE -D__STDC_LIMIT_MACROS -D__STDC_CONSTANT_MACROS -ftime-report -emit-llvm-bc -o t.o</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;"><br></span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;">[LLVM pass timers]</span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"><br>
</span></font></div><div><div><font face="Monaco" size="3"><span style="font-size: 11px;">===-------------------------------------------------------------------------===</span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"> Miscellaneous Ungrouped Timers</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;">===-------------------------------------------------------------------------===</span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"><br>
</span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"> ---User Time--- --System Time-- --User+System-- ---Wall Time--- --- Name ---</span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"> 0.8070 ( 87.2%) 0.0550 ( 73.7%) 0.8620 ( 86.2%) 0.8620 ( 86.2%) Clang front-end timer</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;"> 0.0747 ( 8.1%) 0.0090 ( 12.0%) 0.0837 ( 8.4%) 0.0840 ( 8.4%) LLVM IR Generation Time</span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"> 0.0435 ( 4.7%) 0.0106 ( 14.3%) 0.0541 ( 5.4%) 0.0541 ( 5.4%) Code Generation Time</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;"> 0.9251 (100.0%) 0.0746 (100.0%) 0.9998 (100.0%) 1.0001 (100.0%) Total</span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"><br>
</span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"><br></span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;">real</span></font><span style="white-space: pre-wrap;"><font face="Monaco" size="3"><span style="font-size: 11px;"> </span></font></span><font face="Monaco" size="3"><span style="font-size: 11px;">0m0.903s</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;">user</span></font><span style="white-space: pre-wrap;"><font face="Monaco" size="3"><span style="font-size: 11px;"> </span></font></span><font face="Monaco" size="3"><span style="font-size: 11px;">0m0.827s</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;">sys</span></font><span style="white-space: pre-wrap;"><font face="Monaco" size="3"><span style="font-size: 11px;"> </span></font></span><font face="Monaco" size="3"><span style="font-size: 11px;">0m0.074s</span></font></div>
</div><div><font face="Monaco" size="3"><span style="font-size: 11px;"><br></span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"><br></span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"><br>
</span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;">> time clang -cc1 lib/VMCore/Dominators.cpp -Iinclude -Ilib/VMCore -D_DEBUG -D_GNU_SOURCE -D__STDC_LIMIT_MACROS -D__STDC_CONSTANT_MACROS -ftime-report -fsyntax-only</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;"><br></span></font></div><div><div><font face="Monaco" size="3"><span style="font-size: 11px;">===-------------------------------------------------------------------------===</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;"> Miscellaneous Ungrouped Timers</span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;">===-------------------------------------------------------------------------===</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;"><br></span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"> ---User Time--- --System Time-- --User+System-- ---Wall Time--- --- Name ---</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;"> 0.6823 (100.0%) 0.0317 (100.0%) 0.7139 (100.0%) 0.7139 (100.0%) Clang front-end timer</span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"> 0.6823 (100.0%) 0.0317 (100.0%) 0.7139 (100.0%) 0.7139 (100.0%) Total</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;"><br></span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;"><br></span></font></div><div><font face="Monaco" size="3"><span style="font-size: 11px;">real</span></font><span style="white-space: pre-wrap;"><font face="Monaco" size="3"><span style="font-size: 11px;"> </span></font></span><font face="Monaco" size="3"><span style="font-size: 11px;">0m0.736s</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;">user</span></font><span style="white-space: pre-wrap;"><font face="Monaco" size="3"><span style="font-size: 11px;"> </span></font></span><font face="Monaco" size="3"><span style="font-size: 11px;">0m0.690s</span></font></div>
<div><font face="Monaco" size="3"><span style="font-size: 11px;">sys</span></font><span style="white-space: pre-wrap;"><font face="Monaco" size="3"><span style="font-size: 11px;"> </span></font></span><font face="Monaco" size="3"><span style="font-size: 11px;">0m0.043s</span></font></div>
</div><div><br></div><div><br></div><div><div><br></div><div>Why the difference, am I doing something wrong ?</div></div><div><br></div><div>-Argiris</div></div><br>_______________________________________________<br>
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