On Mon, Apr 19, 2021 at 05:33:03PM -0400, Len Brown wrote: > For this to happen, every thread would not only have to include/link-with > code that uses AMX, but that code would have to *run*.
It looks like either I'm not expressing myself clearly enough or you're not reading my text: the *library* does that decision automatically! Which means *every* possible thread on the system. Which means, *every* thread has a fat 8K buffer attached to it because the library uses AMX on its behalf by *default*. > I'm sure that the AI guys are super excited about matrix multiplication, > but I have a hard time imagining why grep(1) would find a use for it. It doesn't matter if you're imagining it or not - what matters is if the decision whether the thread uses AMX or not is put in the hands of the thread and *NOT* in the hands of the library. Which means, majority of the threads should not allow AMX and only a handful who do, will have to explicitly state that. And the library will have to comply. Not the library decides for every thread itself because the feature's there. > Indeed, if anyone expected AMX to be used by every task, we would have > never gone to the trouble of inventing the XFD hardware to support the > kernel's lazy 8KB buffer allocation. If it gives me fat-buffers-off-by-default and on only for a handful of threads which really want it and *request* it *explicitly*, sure, whatever gets the job done. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette