On Tue, Aug 09, 2005 at 07:00:24PM +0200, Christoph Hermanns wrote: > >>When i run the runvdr script manually, it took also a few seconds before > >>the picture is shown on tv. Can this startup be speeded up ? > >>Any hints are welcome. > > > >Use OProfile to identify the bottlenecks in vdr startup. > > > What is OProfile ? Is it part of any standard gcc package ? > From where can I get OProfile ? OProfile <http://oprofile.sourceforge.net/> is a continuous profiler that is independent of any compiler. It merely produces more readable output if you compile the code with gcc -g. No compile-time, link-time or run-time instrumentation is needed, as is the case with gprof, efence and valgrind, respectively. Instead, OProfile makes use of the performance counters embedded in any modern processor (I guess Pentium and later). The performance penalty depends on the accuracy requested, but typically it is a few percent only. The tool is comparable to DEC (then Compaq then HP) DCPI and Intel VTune. I've used OProfile on Intel Celeron, Intel Pentium M and AMD Opteron, maybe even the AMD K6-2, on 2.4 and 2.6 series kernels. Be sure to enable the local APIC, or otherwise the NMI based performance counter interrupts won't be available. On my vdr box, I have tuned the softdevice plugin based on OProfile measurements. Generally, for measuring start-up bottlenecks, I think you'd better use bootchart. I haven't tried it, since apparently it hasn't been packaged for Debian GNU/Linux. Marko
