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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 24B09C433E0 for ; Wed, 8 Jul 2020 08:41:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E55FE221F1 for ; Wed, 8 Jul 2020 08:41:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="s35D4xLy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728306AbgGHIl4 (ORCPT ); Wed, 8 Jul 2020 04:41:56 -0400 Received: from casper.infradead.org ([90.155.50.34]:57892 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725789AbgGHIl4 (ORCPT ); Wed, 8 Jul 2020 04:41:56 -0400 X-Greylist: delayed 512 seconds by postgrey-1.27 at vger.kernel.org; Wed, 08 Jul 2020 04:41:55 EDT DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=S32XUF0JR40sOoi2lYA1Jt2WlEew0VlzGuJ1gwYbhcU=; b=s35D4xLyvnkYZU4YcWf+9NjRFK qAGphMcWSVhYkoJc8aLz2jh51DodnUkao4ypjVVvtlh5fcEIsMpk6UdXCby8V2qdZA2gSM5VTx11d ejcgbzpQUBqwaR783SFDpecCm7eKgFdgoL4fECk9Qy30bGquxIr924rnywePvDNug5/GOl4mBqpIf yhYDUhFAoVr+rZtcrUHltrwRK7hN7qpv20iSjblFycKsMdUlki/Rvlx96bthlu203IRbVK2rv+Qyz fe6lVWcbvlapeHkqUU1cRfS5tDsGg7qLw6HfdJdLjRTuWghNE1CJUhLCA2Q5UKIbSoK08YZTIcjeG XvtIgbgA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jt5df-0008Ee-Rc; Wed, 08 Jul 2020 08:41:16 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id BAE6F304D58; Wed, 8 Jul 2020 10:41:06 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A7CDA203D34DE; Wed, 8 Jul 2020 10:41:06 +0200 (CEST) Date: Wed, 8 Jul 2020 10:41:06 +0200 From: Peter Zijlstra To: Nicholas Piggin Cc: linuxppc-dev@lists.ozlabs.org, Waiman Long , Anton Blanchard , Boqun Feng , kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , virtualization@lists.linux-foundation.org, Will Deacon Subject: Re: [PATCH v3 0/6] powerpc: queued spinlocks and rwlocks Message-ID: <20200708084106.GE597537@hirez.programming.kicks-ass.net> References: <20200706043540.1563616-1-npiggin@gmail.com> <24f75d2c-60cd-2766-4aab-1a3b1c80646e@redhat.com> <1594101082.hfq9x5yact.astroid@bobo.none> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1594101082.hfq9x5yact.astroid@bobo.none> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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