linux-kernel - [PATCH] perf, tools: Add PERF

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <1410823033-2119-1-git-send-email-andi@firstfloor.org>
Date:	Mon, 15 Sep 2014 16:17:13 -0700
From:	Andi Kleen <andi@...stfloor.org>
To:	jolsa@...hat.com
Cc:	linux-kernel@...r.kernel.org, namhyung@...nel.org, acme@...nel.org,
	mingo@...nel.org, peterz@...radead.org,
	Andi Kleen <ak@...ux.intel.com>
Subject: [PATCH] perf, tools: Add PERF_PID

From: Andi Kleen <ak@...ux.intel.com>

It's currently difficult to filter out perf itself using a filter.
This can give cascading effects during IO tracing when the IO
perf does itself causes more trace output.

The best way to filter is to use the pid. But it's difficult to get the pid
of perf without using hacks.

Add a PERF_PID meta variable to the perf filter that contains the current pid.

With this patch the following works

% perf record -e syscalls:sys_enter_write -a --filter 'common_pid != PERF_PID' ...

This won't work for more complex perf pipe lines with multiple processes,
but at least solves the problem nicely for a single perf.

v2: Remove debug code. Don't use zero padding (Namhyung)
v3: Correct patch.
v4: Handle arbitary pid length.
Acked-by: Namhyung Kim <namhyung@...nel.org>
Signed-off-by: Andi Kleen <ak@...ux.intel.com>
---
 tools/perf/Documentation/perf-record.txt |  2 +-
 tools/perf/util/parse-events.c           | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index d460049..b6c5e51 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -41,7 +41,7 @@ OPTIONS
           'mem:0x1000:rw'.
 
 --filter=<filter>::
-        Event filter.
+        Event filter. PERF_PID represents the perf pid.
 
 -a::
 --all-cpus::
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 1e15df1..f974941 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -967,6 +967,8 @@ int parse_filter(const struct option *opt, const char *str,
 {
 	struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
 	struct perf_evsel *last = NULL;
+	char *pid, buf[30], *p, *o;
+	int len, plen;
 
 	if (evlist->nr_entries > 0)
 		last = perf_evlist__last(evlist);
@@ -977,12 +979,28 @@ int parse_filter(const struct option *opt, const char *str,
 		return -1;
 	}
 
-	last->filter = strdup(str);
+	plen = sprintf(buf, "%d", getpid());
+	len = strlen(str) + 1;
+	for (pid = strstr(str, "PERF_PID"); pid;
+	     pid = strstr(pid + 1, "PERF_PID")) {
+		len += plen - 8;
+	}
+
+	last->filter = malloc(len);
 	if (last->filter == NULL) {
 		fprintf(stderr, "not enough memory to hold filter string\n");
 		return -1;
 	}
 
+	o = last->filter;
+	for (p = str; *p; ) {
+		if (*p == 'P' && !strncmp(p, "PERF_PID", 8)) {
+			strcpy(o, buf);
+			o += plen;
+			p += sizeof("PERF_PID") - 1;
+		} else
+			*o++ = *p++;
+	}
 	return 0;
 }
 
-- 
1.9.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/