From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f177.google.com (mail-pd0-f177.google.com [209.85.192.177]) by kanga.kvack.org (Postfix) with ESMTP id 05CE16B0032 for ; Mon, 8 Jun 2015 14:30:21 -0400 (EDT) Received: by pdbnf5 with SMTP id nf5so110491390pdb.2 for ; Mon, 08 Jun 2015 11:30:20 -0700 (PDT) Received: from mga14.intel.com (mga14.intel.com. [192.55.52.115]) by mx.google.com with ESMTP id pw8si5314515pdb.85.2015.06.08.11.30.19 for ; Mon, 08 Jun 2015 11:30:20 -0700 (PDT) Message-ID: <5575DD33.3000400@intel.com> Date: Mon, 08 Jun 2015 11:21:39 -0700 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [PATCH 0/3] TLB flush multiple pages per IPI v5 References: <1433767854-24408-1-git-send-email-mgorman@suse.de> <20150608174551.GA27558@gmail.com> In-Reply-To: <20150608174551.GA27558@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Ingo Molnar , Mel Gorman Cc: Andrew Morton , Rik van Riel , Hugh Dickins , Minchan Kim , Andi Kleen , H Peter Anvin , Linux-MM , LKML , Linus Torvalds , Peter Zijlstra , Thomas Gleixner On 06/08/2015 10:45 AM, Ingo Molnar wrote: > As per my measurements the __flush_tlb_single() primitive (which you use in patch > #2) is very expensive on most Intel and AMD CPUs. It barely makes sense for a 2 > pages and gets exponentially worse. It's probably done in microcode and its > performance is horrible. I discussed this a bit in commit a5102476a2. I'd be curious what numbers you came up with. But, don't we have to take in to account the cost of refilling the TLB in addition to the cost of emptying it? The TLB size is historically increasing on a per-core basis, so isn't this refill cost only going to get worse? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org