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=-5.2 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,URIBL_BLOCKED,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 8C21DC433FE for ; Sat, 5 Dec 2020 20:42:43 +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 4733F230F9 for ; Sat, 5 Dec 2020 20:42:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4733F230F9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ucw.cz 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-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-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=O87zrPhMufDSV+pZ56AH3EEQSLHr+E9bDJ11FCfm6Uo=; b=uGW+7u5PhjNKjBqtcmLIIH41/ 6vdS0PR62MXHJ7JEo2qRUK6NedGJQilcW5tBHMitTFjjoSxEhkhmDzaMXJoZZXdKdZDK1HX4SUJ8N Yfgj0h3vtwUU/fqCdrC3qV7om78nzmxdKA60cyLCr4Fi7wDG0McOg7nGQ+BXM9ke0CHXRSsgGHEId 3Id7keWgX/RQ5ZAq+w+yjtPJWvg1CNeHeGUHEajQlvurmi3sW7VC3+AT4vcY6eCpQKpj/5/a7U5/g ocARbC6Jooo7nN3IzESyQqqkZg2cnFIbHXUmQrl+7VN0Jwq9j7UxZptrenaJ0GF/JkIzhYOvfK/uS f5ch/kibg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kleMV-0001yP-Hf; Sat, 05 Dec 2020 20:40:59 +0000 Received: from jabberwock.ucw.cz ([46.255.230.98]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kleMR-0001xg-81 for linux-arm-kernel@lists.infradead.org; Sat, 05 Dec 2020 20:40:56 +0000 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 506DF1C0B7C; Sat, 5 Dec 2020 21:40:50 +0100 (CET) Date: Sat, 5 Dec 2020 21:40:49 +0100 From: Pavel Machek To: Alex Belits Subject: Re: [PATCH v5 0/9] "Task_isolation" mode Message-ID: <20201205204049.GA8578@amd> References: <8d887e59ca713726f4fcb25a316e1e932b02823e.camel@marvell.com> MIME-Version: 1.0 In-Reply-To: <8d887e59ca713726f4fcb25a316e1e932b02823e.camel@marvell.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201205_154055_453108_535F3959 X-CRM114-Status: GOOD ( 14.72 ) 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: "linux-arch@vger.kernel.org" , "nitesh@redhat.com" , "pauld@redhat.com" , "catalin.marinas@arm.com" , "peterz@infradead.org" , "linux-api@vger.kernel.org" , "frederic@kernel.org" , "mtosatti@redhat.com" , "linux-kernel@vger.kernel.org" , "rostedt@goodmis.org" , "mingo@kernel.org" , "leon@sidebranch.com" , "netdev@vger.kernel.org" , "peterx@redhat.com" , "trix@redhat.com" , Prasun Kapoor , "tglx@linutronix.de" , "will@kernel.org" , "davem@davemloft.net" , "linux-arm-kernel@lists.infradead.org" Content-Type: multipart/mixed; boundary="===============0235810999309162892==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============0235810999309162892== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="u3/rZRmxL6MmkK24" Content-Disposition: inline --u3/rZRmxL6MmkK24 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > General description >=20 > This is the result of development and maintenance of task isolation > functionality that originally started based on task isolation patch > v15 and was later updated to include v16. It provided predictable > environment for userspace tasks running on arm64 processors alongside > with full-featured Linux environment. It is intended to provide > reliable interruption-free environment from the point when a userspace > task enters isolation and until the moment it leaves isolation or > receives a signal intentionally sent to it, and was successfully used > for this purpose. While CPU isolation with nohz provides an > environment that is close to this requirement, the remaining IPIs and > other disturbances keep it from being usable for tasks that require > complete predictability of CPU timing. So... what kind of guarantees does this aim to provide / what tasks it is useful for? For real time response, we have other approaches. If you want to guarantee performnace of the "isolated" task... I don't see how that works. Other tasks on the system still compete for DRAM bandwidth, caches, etc... So... what is the usecase? Pavel --=20 http://www.livejournal.com/~pavelmachek --u3/rZRmxL6MmkK24 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl/L8FEACgkQMOfwapXb+vJE3wCfYs+cxM/a7TO3oAUetWlr1POn XBIAn3IURI08m9SC3Yh05MPaBjmvFyYq =Y8jH -----END PGP SIGNATURE----- --u3/rZRmxL6MmkK24-- --===============0235810999309162892== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============0235810999309162892==--