From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas-Mich Richter Subject: Re: [PATCH 2/3] perf alias: Rebuild alias expression string to make it comparable Date: Fri, 15 Jun 2018 11:09:05 +0200 Message-ID: References: <20180614114845.41221-1-tmricht@linux.ibm.com> <20180614114845.41221-2-tmricht@linux.ibm.com> <809ff562-511d-26e9-bac3-e8f7b84666e5@us.ibm.com> <20180615081242.GF5082@krava> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20180615081242.GF5082@krava> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Jiri Olsa , Paul Clarke Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, acme@kernel.org, brueckner@linux.vnet.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com List-Id: linux-perf-users.vger.kernel.org On 06/15/2018 10:12 AM, Jiri Olsa wrote: > On Thu, Jun 14, 2018 at 08:53:14AM -0500, Paul Clarke wrote: > > SNIP > >>> + if (ret) >>> + ret += scnprintf(newval + ret, sizeof(newval) - ret, >>> + ","); >>> + if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM) >>> + ret += scnprintf(newval + ret, sizeof(newval) - ret, >>> + "%s=%#x", term->config, term->val.num); >>> + else if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR) >>> + ret += scnprintf(newval + ret, sizeof(newval) - ret, >>> + "%s=%s", term->config, term->val.str); >> >> If we exceed 256, we just suddenly terminate the rebuilding without reporting any issues. >> >>> + } >>> + >>> alias->name = strdup(name); >>> if (dir) { >>> /* >>> @@ -285,7 +308,7 @@ static int __perf_pmu__new_alias(struct list_head *list, char *dir, char *name, >>> snprintf(alias->unit, sizeof(alias->unit), "%s", unit); >>> } >>> alias->per_pkg = perpkg && sscanf(perpkg, "%d", &num) == 1 && num == 1; >>> - alias->str = strdup(val); >>> + alias->str = strdup(newval); > > hum, how is newval different from val? AFAICS it's the same > Not really, depends on the platform, here is some debug output from s390: root@s35lp76 perf]# ./perf stat -e tx_nc_tend -- ~/mytesttx 1 >/tmp/111 Performance counter stats for '/root/mytesttx 1': 1 tx_nc_tend 0.001050150 seconds time elapsed [root@s35lp76 perf]# fgrep -i tx_nc_tend /tmp/111 __perf_pmu__new_alias TX_NC_TEND val:event=0x008d newval:event=0x8d __perf_pmu__new_alias tx_nc_tend val:event=0x8d newval:event=0x8d TX_NC_TEND 1 rc 8 [root@s35lp76 perf]# On s390 the events in the PMU sysfs file are printed with leading zeroes. This means the strcmp() of alias->str differs, but the contents is logically identical. (Same of some files contains spaces). Thats why I do the rewrite of val into newval. The alias name does not match too, but we use strcasecmp() to ignore case. Hope this helps. -- Thomas Richter, Dept 3303, IBM s390 Linux Development, Boeblingen, Germany -- Vorsitzende des Aufsichtsrats: Martina Koederitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294