From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: Re: [PATCH v9 00/27] x86: load FPU registers on return to userland Date: Thu, 4 Apr 2019 16:31:03 +0200 Message-ID: <20190404143103.k7ycnblyefxswf67@linutronix.de> References: <20190403164156.19645-1-bigeasy@linutronix.de> <20190404141409.upfk5z4re3pyvxzn@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: David Laight , "linux-kernel@vger.kernel.org" , "x86@kernel.org" , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , "kvm@vger.kernel.org" , "Jason A. Donenfeld" , Rik van Riel , Dave Hansen To: Andy Lutomirski Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 2019-04-04 07:26:37 [-0700], Andy Lutomirski wrote: > I think that David was asking whether we could make kernel_fpu_begin() > regions sometimes be preemptible. The answer is presumably yes, but I > think that should be a separate effort, and it should be justified > with improved performance above and beyond what we get with Jason's > simd_get() stuff. Last time I checked we had no very SIMD loops unless you count $ALG over 1 MiB data or so. And in that case you could use the kernel_fpu_begin()/end combo after a complete SIMD loop. I would like see that at least while going from one page to the next. Sebastian