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=-2.2 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham 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 54701C433F4 for ; Fri, 31 Aug 2018 10:49:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EAF0220839 for ; Fri, 31 Aug 2018 10:49:52 +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="HlX+bc7D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EAF0220839 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727612AbeHaO4p (ORCPT ); Fri, 31 Aug 2018 10:56:45 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:50226 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726990AbeHaO4p (ORCPT ); Fri, 31 Aug 2018 10:56:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=yKxjqEbWTrOxvTGzinmdWdVD8Qs54eCTbTXOBVFsEhI=; b=HlX+bc7Dth8gnFhCQILmvr1D7 rGddCvBvG7AgDsOeKMjg9+hhkykIZFKdUSecb31xMYjx1U1uXJPnu4diydEnx4r4rNUxJnKAmn05U diwhfGOUk2SqQxd60bD2TMSTrW0lDM8rcy2fpoBSGdjVO0n7xp22Wzqpf/3eXMWZg099YPKJRv3rt zQU/iucix7BPrrVpGU2vL60agCbN1orMrD+Ud+Uo9bpYU7IhHFdsWBOrXjrJZuR1kS2e6jBcg+Gae VsaqeImXbNRedTABYk1Qb5LlIJHUFZYulilMUz4X4fwCF46toyVFqdV3GPGiwmhSyjY1RHuw/MpRj DBFaUPadg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fvgzr-0001uG-St; Fri, 31 Aug 2018 10:49:48 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id C4C862024D425; Fri, 31 Aug 2018 12:49:45 +0200 (CEST) Date: Fri, 31 Aug 2018 12:49:45 +0200 From: Peter Zijlstra To: Nicholas Piggin Cc: Will Deacon , Linus Torvalds , Linux Kernel Mailing List , Benjamin Herrenschmidt , Catalin Marinas , linux-arm-kernel , "Aneesh Kumar K.V" Subject: Re: [PATCH 00/12] Avoid synchronous TLB invalidation for intermediate page-table entries on arm64 Message-ID: <20180831104945.GI24124@hirez.programming.kicks-ass.net> References: <1535645747-9823-1-git-send-email-will.deacon@arm.com> <20180831110054.475a3534@roar.ozlabs.ibm.com> <20180831095417.GF13166@arm.com> <20180831101014.GG24124@hirez.programming.kicks-ass.net> <20180831203234.7b8f4d13@roar.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180831203234.7b8f4d13@roar.ozlabs.ibm.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 31, 2018 at 08:32:34PM +1000, Nicholas Piggin wrote: > Oh gee, I suppose. powerpc hash is kind of interesting because it's > crazy, Aneesh knows that code a lot better than I do. radix modulo > some minor details of exact instructions is fairly like x86 The whole TLB broadcast vs explicit IPIs is a fairly big difference in my book. Anyway, have you guys tried the explicit IPI approach? Depending on how IPIs are routed vs broadcasts it might save a little bus traffic. No point in getting all CPUs to process the TLBI when there's only a hand full that really need it. OTOH, I suppose the broadcast thing has been optimized to death on the hardware side, so who knows..