From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id D4F7AC07D5C for ; Thu, 14 Jun 2018 13:17:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8B03A208B8 for ; Thu, 14 Jun 2018 13:17:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8B03A208B8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=us.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755107AbeFNNRy (ORCPT ); Thu, 14 Jun 2018 09:17:54 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:47352 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754885AbeFNNRx (ORCPT ); Thu, 14 Jun 2018 09:17:53 -0400 Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w5EDFJlc015441 for ; Thu, 14 Jun 2018 09:17:52 -0400 Received: from e13.ny.us.ibm.com (e13.ny.us.ibm.com [129.33.205.203]) by mx0b-001b2d01.pphosted.com with ESMTP id 2jkpfwqgmn-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 14 Jun 2018 09:17:52 -0400 Received: from localhost by e13.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 14 Jun 2018 09:17:50 -0400 Received: from b01ledav005.gho.pok.ibm.com (b01ledav005.gho.pok.ibm.com [9.57.199.110]) by b01cxnp23034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w5EDHmxW9109996 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 14 Jun 2018 13:17:48 GMT Received: from b01ledav005.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E649EAE060; Thu, 14 Jun 2018 09:17:55 -0400 (EDT) Received: from b01ledav005.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2B9F0AE05C; Thu, 14 Jun 2018 09:17:55 -0400 (EDT) Received: from oc3272150783.ibm.com (unknown [9.80.215.247]) by b01ledav005.gho.pok.ibm.com (Postfix) with ESMTPS; Thu, 14 Jun 2018 09:17:55 -0400 (EDT) Subject: Re: [PATCH 1/3] perf alias: Remove trailing newline when reading sysfs files To: Thomas Richter , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, acme@kernel.org, jolsa@redhat.com Cc: brueckner@linux.vnet.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com References: <20180614114845.41221-1-tmricht@linux.ibm.com> From: Paul Clarke Date: Thu, 14 Jun 2018 08:17:47 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180614114845.41221-1-tmricht@linux.ibm.com> Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18061413-0064-0000-0000-0000031B3212 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009189; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000265; SDB=6.01046847; UDB=6.00536174; IPR=6.00825821; MB=3.00021643; MTD=3.00000008; XFM=3.00000015; UTC=2018-06-14 13:17:51 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18061413-0065-0000-0000-00003997C631 Message-Id: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-06-14_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1806140149 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/14/2018 06:48 AM, Thomas Richter wrote: > Remove a trailing newline when reading sysfs file contents > such as /sys/devices/cpum_cf/events/TX_NC_TEND. > This show when verbose option -v is used. > > Output before: > tx_nc_tend -> 'cpum_cf'/'event=0x008d > '/ > > Output after: > tx_nc_tend -> 'cpum_cf'/'event=0x8d'/ > > Signed-off-by: Thomas Richter > --- > tools/perf/util/pmu.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c > index 7878934ebb23..26c79a9c4142 100644 > --- a/tools/perf/util/pmu.c > +++ b/tools/perf/util/pmu.c > @@ -294,7 +294,7 @@ static int __perf_pmu__new_alias(struct list_head *list, char *dir, char *name, > > static int perf_pmu__new_alias(struct list_head *list, char *dir, char *name, FILE *file) > { > - char buf[256]; > + char *cp, buf[256]; > int ret; > > ret = fread(buf, 1, sizeof(buf), file); > @@ -303,6 +303,11 @@ static int perf_pmu__new_alias(struct list_head *list, char *dir, char *name, FI > > buf[ret] = 0; > > + /* Remove trailing newline from sysfs file */ > + cp = strrchr(buf, '\n'); > + if (cp) > + *cp = '\0'; A nit, perhaps, but this will search backwards through the entire string if a newline is not found, which is the most common case, I presume. Would it be more efficient to just look at the last character? Something like: i = strlen(buf); if (i > 0 && buf[i-1] == '\n') buf[i-1] = '\0'; > + > return __perf_pmu__new_alias(list, dir, name, NULL, buf, NULL, NULL, NULL, > NULL, NULL, NULL); > } > PC