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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 D75B4C4361B for ; Sat, 19 Dec 2020 02:05:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA8A723BCB for ; Sat, 19 Dec 2020 02:05:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725966AbgLSCFh (ORCPT ); Fri, 18 Dec 2020 21:05:37 -0500 Received: from helcar.hmeau.com ([216.24.177.18]:41518 "EHLO fornost.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725940AbgLSCFh (ORCPT ); Fri, 18 Dec 2020 21:05:37 -0500 Received: from [192.168.103.7] (helo=gwarestrin.arnor.me.apana.org.au) by fornost.hmeau.com with smtp (Exim 4.92 #5 (Debian)) id 1kqRbX-00054x-AV; Sat, 19 Dec 2020 13:04:20 +1100 Received: by gwarestrin.arnor.me.apana.org.au (sSMTP sendmail emulation); Sat, 19 Dec 2020 13:04:33 +1100 Date: Sat, 19 Dec 2020 13:04:33 +1100 From: Herbert Xu To: Ard Biesheuvel Cc: linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Dave Martin , Mark Brown , Eric Biggers , Will Deacon , Catalin Marinas , Thomas Gleixner , Peter Zijlstra , Sebastian Andrzej Siewior , Ingo Molnar Subject: Re: [RFC PATCH 0/5] running kernel mode SIMD with softirqs disabled Message-ID: <20201219020433.GA11077@gondor.apana.org.au> References: <20201218170106.23280-1-ardb@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201218170106.23280-1-ardb@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Fri, Dec 18, 2020 at 06:01:01PM +0100, Ard Biesheuvel wrote: > > Questions: > - what did I miss or break horribly? > - does any of this matter for RT? AIUI, RT runs softirqs from a dedicated > kthread, so I don't think it cares. > - what would be a reasonable upper bound to keep softirqs disabled? I suppose > 100s of cycles or less is overkill, but I'm not sure how to derive a better > answer. > - could we do the same on x86, now that kernel_fpu_begin/end is no longer > expensive? If this approach works not only would it allow us to support the synchronous users better, it would also allow us to remove loads of cruft in the Crypto API that exist solely to support these SIMD code paths. So I eagerly await the assessment of the scheduler/RT folks on this approach. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt 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=-5.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 92D05C4361B for ; Sat, 19 Dec 2020 02:06:52 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2C32B23BCC for ; Sat, 19 Dec 2020 02:06:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2C32B23BCC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gondor.apana.org.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=zThT6SOPqPJK2GFGcy0uzlEEa0qJzIm0ADFP4abcd14=; b=DYP5e4FuwhBt1TZKILzBceIV1 cOeLHMJn7GTgmNoo6eGwqzhP/e2sRj0EqJsgBAtD7zllWPn3rJ4eFf8Q9x/jRZdZ78zfLae2ZnJaZ 0mopghNjxaNBhnVzI3J9BjjBuBSgvqMlE6+eqEo/imZmKk44z/wuF3bMulDgBBVGbgXom1ygRGdZs WCOTlZ2vth+c7LzEiy/2tu+nfP6FDVUZorZfeT/bewqv7KsHNHl4TGkrQw0jThsZ+HvFldRMJZR7q UnKw0m9emoh9IHf+2sYYDSxdmcrMPRYgz1bKxxzSTQVb0vgAvwr7X+HCcPgDTYCU/oYphEMWTmMG7 KsqgPQMMg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kqRcA-0000Ls-Qv; Sat, 19 Dec 2020 02:04:58 +0000 Received: from helcar.hmeau.com ([216.24.177.18] helo=fornost.hmeau.com) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kqRc6-0000LN-Vv for linux-arm-kernel@lists.infradead.org; Sat, 19 Dec 2020 02:04:57 +0000 Received: from [192.168.103.7] (helo=gwarestrin.arnor.me.apana.org.au) by fornost.hmeau.com with smtp (Exim 4.92 #5 (Debian)) id 1kqRbX-00054x-AV; Sat, 19 Dec 2020 13:04:20 +1100 Received: by gwarestrin.arnor.me.apana.org.au (sSMTP sendmail emulation); Sat, 19 Dec 2020 13:04:33 +1100 Date: Sat, 19 Dec 2020 13:04:33 +1100 From: Herbert Xu To: Ard Biesheuvel Subject: Re: [RFC PATCH 0/5] running kernel mode SIMD with softirqs disabled Message-ID: <20201219020433.GA11077@gondor.apana.org.au> References: <20201218170106.23280-1-ardb@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201218170106.23280-1-ardb@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201218_210455_041960_3E1C3941 X-CRM114-Status: GOOD ( 15.53 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Zijlstra , Catalin Marinas , Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org, Ingo Molnar , Eric Biggers , Mark Brown , linux-crypto@vger.kernel.org, Thomas Gleixner , Will Deacon , Dave Martin , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Dec 18, 2020 at 06:01:01PM +0100, Ard Biesheuvel wrote: > > Questions: > - what did I miss or break horribly? > - does any of this matter for RT? AIUI, RT runs softirqs from a dedicated > kthread, so I don't think it cares. > - what would be a reasonable upper bound to keep softirqs disabled? I suppose > 100s of cycles or less is overkill, but I'm not sure how to derive a better > answer. > - could we do the same on x86, now that kernel_fpu_begin/end is no longer > expensive? If this approach works not only would it allow us to support the synchronous users better, it would also allow us to remove loads of cruft in the Crypto API that exist solely to support these SIMD code paths. So I eagerly await the assessment of the scheduler/RT folks on this approach. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel