On Fri, Jan 26, 2018 at 1:22 AM, Chintan Pandya <cpandya@xxxxxxxxxxxxxx> wrote: > On 1/25/2018 8:20 PM, Rob Herring wrote: >> >> On Thu, Jan 25, 2018 at 4:14 AM, Chintan Pandya <cpandya@xxxxxxxxxxxxxx> >> wrote: >>> [...] >> I'd guess that there's really only a few phandle lookups that occur >> over and over. > > On my system, there are ~6.7k calls of this API during boot. And after boot it will be near 0 yet we carry the memory usage forever. >> The clock controller, interrupt controller, etc. What >> if you just had a simple array of previously found nodes for a cache >> and of_find_node_by_phandle can check that array first. Probably 8-16 >> entries would be enough. > > I clearly see repeat calling with same phandle. But I have few hundreds of > nodes. > I see hashing as generic optimization which applies equally good to all > sized DT. > Using ~4KB more size to save 400 ms is a good trade-off, I believe. But if you can use 200 bytes and save 350 ms, that would be a better trade off IMO. But we don't know because we have no data. Rob -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
