Re: [Valgrind-users] Switching execution from valgrind to native

[Josef W. <Jos...@gm...>]

On Thursday 05 October 2006 23:19, Nicholas Nethercote wrote:
> On Thu, 5 Oct 2006, Mohit Tiwari wrote:
> 
> > I notice that running the floating point benchmarks (like ammp) takes a
> > substantial time. (ammp took ~15min natively and 1.5 hrs using nulgrind)
> > With Memcheck's ~50X overhead, it might take this 12.5 hrs to finish. Is
> > there a way I can switch between native and valgrind executions of a
> > program, so I could use a phase analyzing software like Simpoint to simulate
> > only certain instructions.
> 
> Depends which tool you're using -- I think Callgrind might have some support 
> for this.

In Callgrind, you temporarily can switch off full instrumentation to get the
speed of nulgrind. Of course, cache simulator is off then, too, and the
cache state will be flushed on such switches.

The instrumentation mode at startup can be specified with
"--instr-atstart=yes/no", interactivly changed with
"callgrind_control -i on/off", and per client request in the code
with CALLGRIND_START/STOP_INSTRUMENTATION.

It probably would be nice to switch it on/off when entering a given
function, but this checking would need instrumentation itself.

Josef