From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47620) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dpVfr-0006yL-6o for qemu-devel@nongnu.org; Wed, 06 Sep 2017 04:27:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dpVfn-0002M3-6D for qemu-devel@nongnu.org; Wed, 06 Sep 2017 04:27:03 -0400 Received: from mail-it0-x22c.google.com ([2607:f8b0:4001:c0b::22c]:34903) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dpVfm-0002KU-W0 for qemu-devel@nongnu.org; Wed, 06 Sep 2017 04:26:59 -0400 Received: by mail-it0-x22c.google.com with SMTP id k186so4654853ith.0 for ; Wed, 06 Sep 2017 01:26:58 -0700 (PDT) Sender: Richard Henderson References: <20170829172326.1131-1-bobby.prani@gmail.com> From: Richard Henderson Message-ID: <8ea5a586-4d19-82db-f4b7-058229dc4124@twiddle.net> Date: Wed, 6 Sep 2017 01:26:54 -0700 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] tcg/softmmu: Increase size of TLB caches List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Pranith Kumar Cc: =?UTF-8?Q?Alex_Benn=c3=a9e?= , qemu-devel On 09/05/2017 05:33 PM, Pranith Kumar wrote: >> This significantly degrades performance of alpha-softmmu. >> It spends about 25% of all cpu time in memset. > > What workload does it degrade for? I will try to reproduce and see > which memset is causing this. emerge --update --ask @world which is a lot of python, iirc. It is the tlb flush memset that is causing this. The tlb has grown from a few kB to 300kB with your patch. r~