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[2620:137:e000::3:5]) by mx.google.com with ESMTPS id b20-20020a17090a991400b0028091c90974si12797907pjp.1.2023.11.21.07.26.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Nov 2023 07:26:44 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:5 as permitted sender) client-ip=2620:137:e000::3:5; Authentication-Results: mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=RyxafyiS; dkim=neutral (no key) header.i=@linutronix.de header.s=2020e header.b=czzsI8C6; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:5 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by groat.vger.email (Postfix) with ESMTP id 133068075281; Tue, 21 Nov 2023 07:26:42 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at groat.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234325AbjKUP0b (ORCPT + 99 others); Tue, 21 Nov 2023 10:26:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234156AbjKUP0a (ORCPT ); Tue, 21 Nov 2023 10:26:30 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FC0CE7 for ; Tue, 21 Nov 2023 07:26:25 -0800 (PST) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1700580384; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Iiq2mbTgBqjsqnzkJji7amx/RmZznpllsmH5eCktL90=; b=RyxafyiSMvaX486br0yP3gT97bwsZMFyYi2PdfIHpdsbz7WWf0ylTqkmvaAF51YnUPaZzT qETxDEgEW9pnOfGkwx4nBYHgDRp+5ovtAnKzRfNfrqMaVY9KJUYRUUXtjoNVOXPu0yLYQu uertVueEOQoUWyWJ9X84+2G9CcGmmPk5wkXNoQlIUaxD0g9GSep2oaMuXq5u4s683vEmdy wLeceGMJqPQWw3BwBN8Q4prtnLPAMzCBOD+QacZZ00WL2SdIrrKC1+AHxqx4b3Bf8D1nxf vpyH+GiPighoiQpigZAq3YhU2kFvm2hVvgT3Uesd8q5JrGAXXbrOsoO7FrcGBQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1700580384; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Iiq2mbTgBqjsqnzkJji7amx/RmZznpllsmH5eCktL90=; b=czzsI8C6cQomtR9dlzFYm1BeCSClo2GYReA+2n5Hdkzb3vt18cv7ETHq+8pMX175ju5ptX QKLT9Tb8gZ4eHABw== To: Peter Zijlstra , x86@kernel.org Cc: linux-kernel@vger.kernel.org, peterz@infradead.org Subject: Re: [PATCH 0/2] x86/entry: Trade cycles In-Reply-To: <20231120143344.584345121@infradead.org> References: <20231120143344.584345121@infradead.org> Date: Tue, 21 Nov 2023 16:26:24 +0100 Message-ID: <87msv7161r.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain X-Spam-Status: No, score=-0.9 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on groat.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (groat.vger.email [0.0.0.0]); Tue, 21 Nov 2023 07:26:42 -0800 (PST) On Mon, Nov 20 2023 at 15:33, Peter Zijlstra wrote: > Two little patches that trade a little performance. First patch optimizes > (although I couldn't get definite numbers showing it makes a difference) the > return to user path by avoiding some PTI specifics in the generic path. > > Second patch then steals some of the won cycles by making a debug check > unconditional. > > This came forth from a discussion with amluto who lamented we only had the > debug check conditional on DEBUG_ENTRY. Reviewed-by: Thomas Gleixner