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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1218DC55ABA for ; Tue, 4 Aug 2026 23:12:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: References:Message-ID:In-Reply-To:Subject:cc: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=4i1mGJ+FRQRfIxKQvXxnnfkifi+5HFhjIAJsj6nqa5k=; b=wyv5ycWfYw2Wt2VEJSekQRFGZU 1jw2b7YaeglAUshohIvRPnZx2NIyfv0IdUj1d72iaK1+d+SGqxvS3DynECXuL87wAP3Ovj0Tm7Ko3 ar4gYKiyPxWenmK/aNDy32I5B8Q40hSzm4K5NQ4KNiS1RJJEa4b7fpo+Th76U81tIsaIjleQgYnRP g1ZzvcO2Htl0J6gGgxmdthUM3Kk/esYhUsoit/Hl1xLB6rgAK+j+4YpvQPULeoWPZb6g73EdVQqGk ZWKj2CObsvtVG1Nj4i4kwRwBIhBpao54gGlt6hzstFfZdaBX9vZohiMffXiDTzrIi3sWmMVDTgWST uI3Igfkg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrOJK-00000002uNT-1Anc; Tue, 04 Aug 2026 23:12:38 +0000 Received: from gentwo.org ([62.72.0.81]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrOJH-00000002uMq-15oK for linux-arm-kernel@lists.infradead.org; Tue, 04 Aug 2026 23:12:36 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gentwo.org; s=default; t=1785880881; bh=4i1mGJ+FRQRfIxKQvXxnnfkifi+5HFhjIAJsj6nqa5k=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=at2yiKLYfZC3fVakZoWLhCksz0PMrkI6/d0TYKBPoXpIGPtfNc7LU+ViWv+A6CxMf GC7DQy0jW4XLySRIheErfnG9B0tvk7yE/mUQWds+3h9H8PtzC63PmrbXcK6D3O7ooq 2NcakzJJtfeuENJUfR891WT/5jvSHVkQBfAfP5dE= Received: by gentwo.org (Postfix, from userid 1003) id 2788540E6B; Tue, 04 Aug 2026 15:01:21 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id 264D540287; Tue, 04 Aug 2026 15:01:21 -0700 (PDT) Date: Tue, 4 Aug 2026 15:01:21 -0700 (PDT) From: "Christoph Lameter (Ampere)" To: "David Hildenbrand (Arm)" cc: "Lorenzo Stoakes (ARM)" , Mark Rutland , Yang Shi , Ryan Roberts , dennis@kernel.org, tj@kernel.org, urezki@gmail.com, catalin.marinas@arm.com, will@kernel.org, akpm@linux-foundation.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Linus Torvalds , Jason Gunthorpe Subject: Re: [RFC v2 PATCH 0/16] Optimize this_cpu_*() ops for non-x86 (ARM64 for this series) In-Reply-To: Message-ID: References: <20260715180455.515692-1-yang@os.amperecomputing.com> <0344c559-1959-4531-9265-d5a5180eb7cd@arm.com> <25d1e09b-53e4-7cd5-87db-b58437e4e690@gentwo.org> <4887267b-dc26-4c33-96ca-8dff054a0d1f@kernel.org> <63ea8156-a109-b2a2-6d35-1c17ad7f1a9d@gentwo.org> <84b31836-1d10-4bec-a469-468b91fd4645@kernel.org> <9f146ce0-4adc-0c00-a2d8-c01b47edc9d1@gentwo.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260804_161235_323044_32F9ED22 X-CRM114-Status: GOOD ( 14.52 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 4 Aug 2026, David Hildenbrand (Arm) wrote: > >> If the proposed solution has a significant benefit over Mark's solution it could > >> be discussed as a next step; and it must be backed with sufficient data to > >> warrant all this complexity here. > > > > You cannot accept that one instruction is faster than the same > > instruction prefixed with another and something else at its tail? > > I am pretty sure that you got exactly what I meant, you likely just don't have > the data to back it up. > > Proof me wrong! Well you seem to have alrady seen the benchmarks that we ran and are running. So I had doubts on your sincerety with this comment. Seemes to be be just there for effect.