linux-kernel - [PATCH 6/7 V2] perf: Add support to dynamically get cacheline size

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Message-Id: <1401461425-209679-1-git-send-email-dzickus@redhat.com>
Date:	Fri, 30 May 2014 10:50:25 -0400
From:	Don Zickus <dzickus@...hat.com>
To:	jolsa@...hat.com
Cc:	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>, namhyung@...il.com,
	eranian@...gle.com, Andi Kleen <andi@...stfloor.org>,
	Don Zickus <dzickus@...hat.com>
Subject: [PATCH 6/7 V2] perf: Add support to dynamically get cacheline size

Different arches may have different cacheline sizes.  Look it up and set
a global variable for reference.

Signed-off-by: Don Zickus <dzickus@...hat.com>

---
V3: remove unneeded cpumap.h (Namhyung Kim)
V2: change to be global and setup in perf.c
    use filename__read_int for setup
---
 tools/perf/perf.c        |  5 +++++
 tools/perf/util/cpumap.c | 27 +++++++++++++++++++++++++++
 tools/perf/util/cpumap.h |  3 +++
 tools/perf/util/util.c   |  1 +
 tools/perf/util/util.h   |  1 +
 5 files changed, 37 insertions(+)

diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index 431798a..dabf08b 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -13,6 +13,7 @@
 #include "util/quote.h"
 #include "util/run-command.h"
 #include "util/parse-events.h"
+#include "util/cpumap.h"
 #include <api/fs/debugfs.h>
 #include <pthread.h>
 
@@ -459,6 +460,10 @@ int main(int argc, const char **argv)
 	/* The page_size is placed in util object. */
 	page_size = sysconf(_SC_PAGE_SIZE);
 
+	/* The cacheline_size is placed in util objet */
+	if (cpu__setup_cacheline_size() < 0) 
+		goto out;
+
 	cmd = perf_extract_argv0_path(argv[0]);
 	if (!cmd)
 		cmd = "perf-help";
diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index c4e55b7..1029982 100644
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -477,3 +477,30 @@ int cpu__setup_cpunode_map(void)
 	closedir(dir1);
 	return 0;
 }
+
+int cpu__setup_cacheline_size(void)
+{
+	const char *mnt;
+	char path[PATH_MAX];
+	int n, size;
+	
+
+	mnt = sysfs__mountpoint();
+	if (!mnt)
+		return -1;
+
+	n = snprintf(path, PATH_MAX, "%s/devices/system/cpu/cpu0/cache/index0/coherency_line_size", mnt);
+	if (n == PATH_MAX) {
+		pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX);
+		return -1;
+	}
+
+	if (filename__read_int(path, &size)) {
+		pr_err("Can not read cacheline size\n");
+		return -1;
+	}
+
+	cacheline_size = size;
+
+	return 0;
+}
diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h
index 61a6548..507d7fd 100644
--- a/tools/perf/util/cpumap.h
+++ b/tools/perf/util/cpumap.h
@@ -5,6 +5,7 @@
 #include <stdbool.h>
 
 #include "perf.h"
+#include "util/util.h"
 #include "util/debug.h"
 
 struct cpu_map {
@@ -81,4 +82,6 @@ static inline int cpu__get_node(int cpu)
 	return cpunode_map[cpu];
 }
 
+int cpu__setup_cacheline_size(void);
+
 #endif /* __PERF_CPUMAP_H */
diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index 7fff6be..95aefa7 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -17,6 +17,7 @@
  * XXX We need to find a better place for these things...
  */
 unsigned int page_size;
+int cacheline_size;
 
 bool test_attr__enabled;
 
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index b03da44..6686436 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -304,6 +304,7 @@ char *rtrim(char *s);
 void dump_stack(void);
 
 extern unsigned int page_size;
+extern int cacheline_size;
 
 void get_term_dimensions(struct winsize *ws);
 
-- 
1.7.11.7

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