From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04A18C4360F for ; Thu, 4 Apr 2019 14:31:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB45420855 for ; Thu, 4 Apr 2019 14:31:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728766AbfDDObI (ORCPT ); Thu, 4 Apr 2019 10:31:08 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:45258 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727165AbfDDObI (ORCPT ); Thu, 4 Apr 2019 10:31:08 -0400 Received: from bigeasy by Galois.linutronix.de with local (Exim 4.80) (envelope-from ) id 1hC3OR-0003iS-M3; Thu, 04 Apr 2019 16:31:03 +0200 Date: Thu, 4 Apr 2019 16:31:03 +0200 From: Sebastian Andrzej Siewior To: Andy Lutomirski 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 Subject: Re: [PATCH v9 00/27] x86: load FPU registers on return to userland 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 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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