No such 'noise' is possible with callgrind, as it's basically simulating the hardware. If you're using a VM it seems like you could still get variation between different runs due to other activity on the host system.
> Cachegrind simulates branch predictors intended to be typical of mainstream desktop/server processors of around 2004.
In other words, the data produced by Callgrind may be suitable to find obvious regressions, but there still may be more regressions which are only relevant on more modern CPUs.
> Cachegrind simulates branch predictors intended to be typical of mainstream desktop/server processors of around 2004.
In other words, the data produced by Callgrind may be suitable to find obvious regressions, but there still may be more regressions which are only relevant on more modern CPUs.