> What would be a better implementation? No delay and simply retry for > five seconds? > > What TPMs are you using for your tests? At least for the TPMs that I > have available for my tests (with a FIFO size of ~256 bytes) I would not > expect any wait states for extend commands. The TPM burstcount is 32. Unfortunately, with this patch set the performance on the pi is worse than without it. Without this patch set we're seeing ~14 secs for a thousand measurements vs. either ~38s or ~23s, depending on the wait sleep length introduced in patch 8/9. This testing was done on a pi with an emulated SPI bus. On systems with a large burstcount, there is no difference, but on systems with a small burstcount, we're seeing an improvement of ~39% (~14s base time, ~8.5 with patches). Does anyone have a system with a TPM on a real SPI bus and is willing to test this patch set? thanks, Mimi
