Investigating Split Locks on x86-64
… With split locks, P-Cores suffer agonizingly poor latency. Split locks between P and E-Cores have just above 7 microseconds of latency, matching Arrow Lake. E-Cores have the best split lock latency. …
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Strix Halo’s Memory Subsystem: Tackling iGPU Challenges
… Latency rises far above the baseline of around 140 ns. I logged average latency over 1 second intervals, and many of those intervals saw latency figures around 200 ns across several games I wrote a microbenchmark to investigate how CPU memory latency is impacted by GPU-sde bandwidth load. …
Microbenchmarking Chipsets for Giggles
… On X670E, hopping over two PROM21 chips brings latency to 921.3 ns over the baseline. Going over the chipset therefore comes with a hefty latency penalty. Going through an extra PROM21 chip further increases latency. …