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While you might test your hard real-time requirements with caches disabled, there's still reason to run the code with caches afterwards. E.g. errors that didn'
by nightcracker 7y ago
While you might test your hard real-time requirements with caches disabled, there's still reason to run the code with caches afterwards.
E.g. errors that didn't match a branch or input scenario during testing which would go over budget without cache, but with cache might prevent a crash.
Another could be power consumption, latency optimization, or improvement of accuracy. E.g. some signal analysis doesn't work at all if the real-time code is above some required Nyquist threshold, but faster performance improves the maximum frequency that can be handled, improving accuracy.
- notacoward 7y agoYou could be right on some of those. That didn't seem to be the prevailing attitude when I worked in that area, but as I said that was a long time ago - and it was in only a few specific sub-domains as well.
- notacoward 7y agoForgot to mention: cache misses can be more expensive than uncached accesses, so testing with caches off and then turning them on in production can be a disaster if you hit a cache-busting access pattern. Always run what you tested.