Be careful of the implicit context [LWN.net]

Be careful of the implicit context

Posted Aug 29, 2007 20:18 UTC (Wed) by renox (guest, #23785)
In reply to: On DTrace envy by oak
Parent article: On DTrace envy

Sorry but 'can be done' is very different from 'can be done usefully' i.e. with DTrace a sysadmin can do the disk profile on a live production system, AFAIK Valgrind cannot do this..

Note that I'm not criticising Valgrind which is a very useful tool, just that the great selling point of DTrace is that it can do systemic tracing on live production system, so sure you can do many things with CPU simulators but it's quite out of topic/context..

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Be careful of the implicit context

Posted Mar 6, 2008 20:41 UTC (Thu) by oak (subscriber, #2786) [Link]

IOgrind has been released a while ago.  Its advantage over live system 
profiling is that the results are deterministic whereas live system 
performance measurements can (according to Meeks) differ as much as 10% 
(on Linux) from run to run.  On a properly designed system, you don't 
(anymore) find that large bottlenecks, they are smaller.

If the bottlenecks are larger, I would assume one could catch them even 
with strace (just strace all applicable processes at the same time).