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> High Precision Event Timers Isn't HPET is just a basic system timer? (That is definitely present on Zen.) You might be thinking of something else? > 256-bit

> High Precision Event Timers Isn't HPET is just a basic system timer? (That is definitely present on Zen.) You might be thinking of something else? > 256-bit execution would be nice, but its not a major hassle in most cases Coming with Zen 2 anyway :)

dragontamer 8y ago
> Isn't HPET is just a basic system timer? (That is definitely present on Zen.) You might be thinking of something else? You're right. I got the names confused. I've edited the post above to use the proper "PEBS" term. Intel's "Precise Event-Based Sampling" is what I was trying to talk about. Intel's PEBS can precisely tell you where a branch-mispredict happens. AMD's default event timers are inaccurate: your branch mispredictions will be all over "add" instructions, and other unrelated stuff. This is because a CPU is looking at roughly ~100 instruction windows (between the pipeline, decoder, and retirement... there's a lot of inaccuracy in determining "where did this branch misprediction happen??"). So when trying to track down a branch-misprediction on AMD systems, you have to switch to the harder to use "Instruction based Profiling" mode. Intel has a simpler PEBS switch which is easier to use IMO.