From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linutronix.de (146.0.238.70:993) by crypto-ml.lab.linutronix.de with IMAP4-SSL for ; 05 Feb 2019 16:45:48 -0000 Received: from mga12.intel.com ([192.55.52.136]) by Galois.linutronix.de with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1gr3r1-00025O-4e for speck@linutronix.de; Tue, 05 Feb 2019 17:45:47 +0100 Date: Tue, 5 Feb 2019 08:45:44 -0800 From: Andi Kleen Subject: [MODERATED] Re: [PATCH v1 6/9] PERFv1 5 Message-ID: <20190205164544.GH31598@tassilo.jf.intel.com> References: <932163848f71fb6ccd855e2d20963be49121042c.1549329178.git.ak@linux.intel.com> <20190205152644.GX17528@hirez.programming.kicks-ass.net> MIME-Version: 1.0 In-Reply-To: <20190205152644.GX17528@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit To: speck@linutronix.de List-ID: > So you know tglx and me have been arguing for the opposite default. This > will 'silently' break stuff that relies on having the counters present > -- and there are people who do indeed rely on that. Right. > > At the same time; by default there are no (with the possible exception > of the NMI watchdog) users of the PMU, It seems there is more and more perf use for various purposes, but it's hard to say. > and I don't think TSX is in fact used by default either. There are workloads that use it by default and need it for performance. > > This means that only people that explicitly use TSX and perf at the same > time are impacted with that default, and the rest will actually work. That's right. -Andi