Hi Dirk, On Tue, Feb 7, 2012 at 10:51 PM, Dirk Behme <dirk.be...@de.bosch.com> wrote: > On 08.02.2012 00:36, Wolfgang Denk wrote: >> >> Dear Graeme Russ, >> >> In message >> <CALButCKfG+guStJP+M5E=nsr34vphzgbrebxquxd6028sw6...@mail.gmail.com> you >> wrote: >>>> >>>> If SPL was to determing the relocation address, it would also have to >>>> read the environment, because there are a number of environment >>>> variables which can cause (dynamically) the relocation address to >>>> change. >>> >>> But this is not neccessarily the case for every board (or even every >>> arch) >> >> >> Not neccessarily, but possible. >> >>> For those boards/arches which CAN calculate the relocation address >>> (either >>> because it is fixed do to npn-variable RAM size, or fixed in relation to >>> the maximum RAM address) why should we prohibit a method of skipping the >>> redundant copy operation in a way which is 100% transparent to everyone >>> else? >> >> >> Can we please focus on unifying the boot process first, before we try >> to come up with micro-optimizations? >> >> Most of the people who complain here that they need to skip >> relocation are probably wrong in at least two accounts: >> >> - They are not actually talking about relocation at all. >> - They don't base their accessment on any real, measured timings, or >> otherwise they would start optimizing completely different areas of >> the code. > > > Maybe they are looking at all areas (including the different ones) of > possible optimizations. And this thread is only one topic (note 1). > > Best regards > > Dirk > > note 1: I agree that the different topics will give more improvement. E.g. > [1]. Looking at that thread, unfortunately there is less discussion than > here while it will give more improvement :( > > [1] http://lists.denx.de/pipermail/u-boot/2012-February/117270.html
But turning on the cache should be trivial - it is already supported so you just need to implement the enable_dcache() function(?) I think. Also make sure that the I-Cache is on as early as possible. Relocation is done with the d-cache off so is slow. Takes about 40ms for me from memory, but we do have things which can speed it up. But d-cache matters more than just about anything. Regards, Simon > > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > http://lists.denx.de/mailman/listinfo/u-boot _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
