Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966285AbdIYUgJ (ORCPT ); Mon, 25 Sep 2017 16:36:09 -0400 Received: from mga04.intel.com ([192.55.52.120]:50732 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934254AbdIYUgI (ORCPT ); Mon, 25 Sep 2017 16:36:08 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,437,1500966000"; d="scan'208";a="155848529" Date: Mon, 25 Sep 2017 13:36:04 -0700 From: Andi Kleen To: kan.liang@intel.com Cc: acme@kernel.org, peterz@infradead.org, mingo@redhat.com, linux-kernel@vger.kernel.org, jolsa@kernel.org, namhyung@kernel.org, adrian.hunter@intel.com, lukasz.odzioba@intel.com Subject: Re: [PATCH RFC V3 5/5] perf top: switch back to overwrite mode Message-ID: <20170925203604.GP4311@tassilo.jf.intel.com> References: <1506370988-56587-1-git-send-email-kan.liang@intel.com> <1506370988-56587-6-git-send-email-kan.liang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1506370988-56587-6-git-send-email-kan.liang@intel.com> User-Agent: Mutt/1.8.3 (2017-05-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 787 Lines: 21 On Mon, Sep 25, 2017 at 01:23:08PM -0700, kan.liang@intel.com wrote: > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c > index 6a0d7ff..ef0b6b1 100644 > --- a/tools/perf/util/evlist.c > +++ b/tools/perf/util/evlist.c > @@ -723,7 +723,10 @@ perf_mmap__read(struct perf_mmap *md, bool check_messup, u64 start, > * In either case, truncate and restart at 'end'. > */ > if (diff > md->mask / 2 || diff < 0) { > - fprintf(stderr, "WARNING: failed to keep up with mmap data.\n"); > + WARN_ONCE(1, "WARNING: failed to keep up with mmap data.\n" > + "Please try increasing the period (-c) or\n" > + "decreasing the freq (-F) or\n" > + "limiting the number of CPUs"); should suggest -C too "limiting the number of CPUs (-C)"); -Andi