Hi Andrew, On 15 September 2017 at 13:20, Andrew Pinski <pins...@gmail.com> wrote: > On Thu, Sep 14, 2017 at 6:28 PM, Kugan Vivekanandarajah > <kugan.vivekanandara...@linaro.org> wrote: >> This patch adds number of hw prefetchers available to >> cpu_prefetch_tune so it can be used in loop unrolling decisions. > > Can you explain the difference between this and num_slots > (PARAM_SIMULTANEOUS_PREFETCHES)? Because it seems like they should be > the same here. > I kept it different for two reason.
1. I am not sure if this would have the same effect on all the micro-architecture. Keeping it separate allows each microarchitecture to enable prefetch loop arrays and aiding hw prefetcher (my goal here) by limiting prefetch streams. 2. The params used for ARAM_SIMULTANEOUS_PREFETCHES seems to be a value determined by experimentation rather than based on functional units in hardware. This also allows tuning them speretaterly. Thanks, Kugan
