From mboxrd@z Thu Jan 1 00:00:00 1970 From: Radim =?utf-8?B?S3LEjW3DocWZ?= Subject: Re: [PATCH] kvm/stats: Update kvm stats to clear on write to their debugfs entry Date: Mon, 17 Oct 2016 15:40:05 +0200 Message-ID: <20161017134004.GA8631@potion> References: <1476424962-7610-1-git-send-email-sjitindarsingh@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, pbonzini@redhat.com To: Suraj Jitindar Singh Return-path: Received: from mx1.redhat.com ([209.132.183.28]:47520 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757735AbcJQNkI (ORCPT ); Mon, 17 Oct 2016 09:40:08 -0400 Content-Disposition: inline In-Reply-To: <1476424962-7610-1-git-send-email-sjitindarsingh@gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: 2016-10-14 17:02+1100, Suraj Jitindar Singh: > Various kvm vm and vcpu stats are provided via debugfs entries. > Currently there is no way to reset these stats back to zero for the system > except by stopping all vms. It is not really resetting, just a special case of current behavior -- top-level stats are a sum of all existing VMs/VCPUs, so we would see 0 if they all had 0. > Add the ability to clear (reset back to zero) these stats on a per stat > basis by writing to the debugfs files. I can see this being used before a test, but the userspace could also read the value instead of writing and subtract it from the value after the test to get a similar result. The userspace-only solution is insufficient? When and what do you zero? > The stats are just reset to zero > irrespective of what is actually written to the file. Sounds good. Setting the val would be as simple, but there shouldn't be a reason to and it is a debug interface, so we can change it anytime. > Signed-off-by: Suraj Jitindar Singh > --- I have applied it to kvm/queue for the moment, thanks.