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Date: Fri, 2 Aug 2013 13:10:51 +0300
From: Adrian Hunter <adrian.hunter@...el.com>
To: Arnaldo Carvalho de Melo <acme@...stprotocols.net>
Cc: linux-kernel@...r.kernel.org, David Ahern <dsahern@...il.com>,
Frederic Weisbecker <fweisbec@...il.com>,
Jiri Olsa <jolsa@...hat.com>, Mike Galbraith <efault@....de>,
Namhyung Kim <namhyung@...il.com>,
Paul Mackerras <paulus@...ba.org>,
Peter Zijlstra <peterz@...radead.org>,
Stephane Eranian <eranian@...gle.com>,
Ingo Molnar <mingo@...nel.org>
Subject: [PATCH V3 09/10] perf tools: add kcore to the object code reading test
Make the "object code reading" test attempt to read from
kcore.
The test uses objdump which struggles with kcore. i.e.
doesn't always work, sometimes takes a long time.
The test has been made to work around those issues.
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
tools/perf/tests/code-reading.c | 75 +++++++++++++++++++++++++++++++++++------
1 file changed, 65 insertions(+), 10 deletions(-)
diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
index 0c7b052..adba5a1 100644
--- a/tools/perf/tests/code-reading.c
+++ b/tools/perf/tests/code-reading.c
@@ -107,6 +107,9 @@ static int read_via_objdump(const char *filename, u64 addr, void *buf,
pr_debug("Objdump command is: %s\n", cmd);
+ /* Ignore objdump errors */
+ strcat(cmd, " 2>/dev/null");
+
f = popen(cmd, "r");
if (!f) {
pr_debug("popen failed\n");
@@ -146,7 +149,8 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode,
pr_debug("File is: %s\n", al.map->dso->long_name);
- if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS) {
+ if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
+ !dso__is_kcore(al.map->dso)) {
pr_debug("Unexpected kernel address - skipping\n");
return 0;
}
@@ -175,6 +179,26 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode,
if (map__load(al.map, NULL))
return -1;
+ /* objdump struggles with kcore - try each map only once */
+ if (dso__is_kcore(al.map->dso)) {
+ static u64 done[1024];
+ static size_t done_cnt;
+ size_t d;
+
+ for (d = 0; d < done_cnt; d++) {
+ if (done[d] == al.map->start) {
+ pr_debug("kcore map tested already");
+ pr_debug(" - skipping\n");
+ return 0;
+ }
+ }
+ if (done_cnt >= ARRAY_SIZE(done)) {
+ pr_debug("Too many kcore maps - skipping\n");
+ return 0;
+ }
+ done[done_cnt++] = al.map->start;
+ }
+
/* Read the object code using objdump */
objdump_addr = map__rip_2objdump(al.map, al.addr);
ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len);
@@ -186,10 +210,19 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode,
if (cpumode == PERF_RECORD_MISC_KERNEL ||
cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
len -= ret;
- if (len)
+ if (len) {
pr_debug("Reducing len to %zu\n", len);
- else
+ } else if (dso__is_kcore(al.map->dso)) {
+ /*
+ * objdump cannot handle very large segments
+ * that may be found in kcore.
+ */
+ pr_debug("objdump failed for kcore");
+ pr_debug(" - skipping\n");
+ return 0;
+ } else {
return -1;
+ }
}
}
if (ret < 0) {
@@ -331,10 +364,12 @@ static void do_something(void)
enum {
TEST_CODE_READING_OK,
TEST_CODE_READING_NO_VMLINUX,
+ TEST_CODE_READING_NO_KCORE,
TEST_CODE_READING_NO_ACCESS,
+ TEST_CODE_READING_NO_KERNEL_OBJ,
};
-static int do_test_code_reading(void)
+static int do_test_code_reading(bool try_kcore)
{
struct machines machines;
struct machine *machine;
@@ -355,7 +390,7 @@ static int do_test_code_reading(void)
int err = -1, ret;
pid_t pid;
struct map *map;
- bool have_vmlinux, excl_kernel = false;
+ bool have_vmlinux, have_kcore, excl_kernel = false;
pid = getpid();
@@ -368,6 +403,10 @@ static int do_test_code_reading(void)
goto out_err;
}
+ /* Force the use of kallsyms instead of vmlinux to try kcore */
+ if (try_kcore)
+ symbol_conf.kallsyms_name = "/proc/kallsyms";
+
/* Load kernel map */
map = machine->vmlinux_maps[MAP__FUNCTION];
ret = map__load(map, NULL);
@@ -375,9 +414,15 @@ static int do_test_code_reading(void)
pr_debug("map__load failed\n");
goto out_err;
}
- have_vmlinux = map->dso->symtab_type == DSO_BINARY_TYPE__VMLINUX;
- /* No point getting kernel events if there is no vmlinux */
- if (!have_vmlinux)
+ have_vmlinux = dso__is_vmlinux(map->dso);
+ have_kcore = dso__is_kcore(map->dso);
+
+ /* 2nd time through we just try kcore */
+ if (try_kcore && !have_kcore)
+ return TEST_CODE_READING_NO_KCORE;
+
+ /* No point getting kernel events if there is no kernel object */
+ if (!have_vmlinux && !have_kcore)
excl_kernel = true;
threads = thread_map__new_by_tid(pid);
@@ -465,7 +510,9 @@ static int do_test_code_reading(void)
if (ret < 0)
goto out_err;
- if (!have_vmlinux)
+ if (!have_vmlinux && !have_kcore && !try_kcore)
+ err = TEST_CODE_READING_NO_KERNEL_OBJ;
+ else if (!have_vmlinux && !try_kcore)
err = TEST_CODE_READING_NO_VMLINUX;
else if (excl_kernel)
err = TEST_CODE_READING_NO_ACCESS;
@@ -492,7 +539,9 @@ int test__code_reading(void)
{
int ret;
- ret = do_test_code_reading();
+ ret = do_test_code_reading(false);
+ if (!ret)
+ ret = do_test_code_reading(true);
switch (ret) {
case TEST_CODE_READING_OK:
@@ -500,9 +549,15 @@ int test__code_reading(void)
case TEST_CODE_READING_NO_VMLINUX:
fprintf(stderr, " (no vmlinux)");
return 0;
+ case TEST_CODE_READING_NO_KCORE:
+ fprintf(stderr, " (no kcore)");
+ return 0;
case TEST_CODE_READING_NO_ACCESS:
fprintf(stderr, " (no access)");
return 0;
+ case TEST_CODE_READING_NO_KERNEL_OBJ:
+ fprintf(stderr, " (no kernel obj)");
+ return 0;
default:
return -1;
};
--
1.7.11.7
--
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