Hi Stefan, On Wed, Dec 5, 2012 at 6:55 PM, Stefan Tauner <stefan.tau...@student.tuwien.ac.at> wrote: > Hi, > > if you would want to measure the instant in time you do something() in > software with a scope or logic analyser (by toggling a pin once) on a > typical x86 PC (e.g. pci, serial, lpt available, ok maybe not THAT > typical anymore ;) running linux, what kind of I/O would you choose? > latency should be minimal, but without major hardware hacks (no > soldering to CPU pins or similar please :)
I did something similar for quantifying latency and jitter for a control system (like a PID loop). What is your margin of error? If you can only tolerate an error of about 1 nanosecond, you may have to take great pains to make sure you have an accurate clock. Some physicists had to do that to resolve their questions: http://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly You could read from a PCI or PCI-e device and a scope or logic analyzer on the bus would know the instant that happened. Hope that helps, David -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot