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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 A51FEC433DF for ; Wed, 8 Jul 2020 23:58:17 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 5052E20659 for ; Wed, 8 Jul 2020 23:58:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JU+GUDGD"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JU+GUDGD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5052E20659 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4B2GTg46KXzDqXt for ; Thu, 9 Jul 2020 09:58:15 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=redhat.com (client-ip=205.139.110.120; helo=us-smtp-1.mimecast.com; envelope-from=longman@redhat.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=JU+GUDGD; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=JU+GUDGD; dkim-atps=neutral Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4B2GPf2JKgzDqkw for ; Thu, 9 Jul 2020 09:54:45 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594252481; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DtrdIs9PFK4eESgNJshnXKkRcQvqs7rbt6XjlBm0KbQ=; b=JU+GUDGD8/h39OEbGcTEdQx4DbJTBABxYYurbs/1H3amYYO24vEdzOP3fdz3rscTH3JV8V UwCQXCpr2UA/IPnWvQ5AE/9yj+3p1ItoKJ5E27T/eLOzUD+83Jd9Dd+lu6CcGqIe/saZG6 aCtlIqtFh1OA6+746aFC7tWfH8Vn9n8= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594252481; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DtrdIs9PFK4eESgNJshnXKkRcQvqs7rbt6XjlBm0KbQ=; b=JU+GUDGD8/h39OEbGcTEdQx4DbJTBABxYYurbs/1H3amYYO24vEdzOP3fdz3rscTH3JV8V UwCQXCpr2UA/IPnWvQ5AE/9yj+3p1ItoKJ5E27T/eLOzUD+83Jd9Dd+lu6CcGqIe/saZG6 aCtlIqtFh1OA6+746aFC7tWfH8Vn9n8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-148-uUzGLLqxNBSRxBpviTCmyg-1; Wed, 08 Jul 2020 19:54:37 -0400 X-MC-Unique: uUzGLLqxNBSRxBpviTCmyg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DA4D98027B1; Wed, 8 Jul 2020 23:54:35 +0000 (UTC) Received: from llong.remote.csb (ovpn-116-205.rdu2.redhat.com [10.10.116.205]) by smtp.corp.redhat.com (Postfix) with ESMTP id 986922C2BC; Wed, 8 Jul 2020 23:54:34 +0000 (UTC) Subject: Re: [PATCH v3 0/6] powerpc: queued spinlocks and rwlocks To: Peter Zijlstra , Nicholas Piggin References: <20200706043540.1563616-1-npiggin@gmail.com> <24f75d2c-60cd-2766-4aab-1a3b1c80646e@redhat.com> <1594101082.hfq9x5yact.astroid@bobo.none> <20200708084106.GE597537@hirez.programming.kicks-ass.net> From: Waiman Long Organization: Red Hat Message-ID: Date: Wed, 8 Jul 2020 19:54:34 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200708084106.GE597537@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, Will Deacon , Boqun Feng , linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, virtualization@lists.linux-foundation.org, Ingo Molnar , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 7/8/20 4:41 AM, Peter Zijlstra wrote: > On Tue, Jul 07, 2020 at 03:57:06PM +1000, Nicholas Piggin wrote: >> Yes, powerpc could certainly get more performance out of the slow >> paths, and then there are a few parameters to tune. > Can you clarify? The slow path is already in use on ARM64 which is weak, > so I doubt there's superfluous serialization present. And Will spend a > fair amount of time on making that thing guarantee forward progressm, so > there just isn't too much room to play. > >> We don't have a good alternate patching for function calls yet, but >> that would be something to do for native vs pv. > Going by your jump_label implementation, support for static_call should > be fairly straight forward too, no? > > https://lkml.kernel.org/r/20200624153024.794671356@infradead.org > Speaking of static_call, I am also looking forward to it. Do you have an idea when that will be merged? Cheers, Longman