perf test: Add -F/--dont-fork option

Adding -F/--dont-fork option to bypass forking for each test. It's
useful for debugging test.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Nilay Vaish <nilayvaish@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1467113345-12669-1-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 37 insertions, 22 deletions

diff --git a/tools/perf/Documentation/perf-test.txt b/tools/perf/Documentation/perf-test.txt
index 31a5c3ea7f74..b329c65d7f40 100644
--- a/tools/perf/Documentation/perf-test.txt
+++ b/tools/perf/Documentation/perf-test.txt
@@ -30,3 +30,7 @@ OPTIONS
 -v::
 --verbose::
         Be more verbose.
+
+-F::
+--dont-fork::
+        Do not fork child for each test, run all tests within single process.
diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index 0e95c20ecf6e..5781c1640eae 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -14,6 +14,8 @@
 #include <subcmd/parse-options.h>
 #include "symbol.h"
 
+static bool dont_fork;
+
 struct test __weak arch_tests[] = {
         {
                 .func = NULL,
@@ -247,7 +249,7 @@ static bool perf_test__matches(struct test *test, int curr, int argc, const char
 
 static int run_test(struct test *test, int subtest)
 {
-        int status, err = -1, child = fork();
+        int status, err = -1, child = dont_fork ? 0 : fork();
         char sbuf[STRERR_BUFSIZE];
 
         if (child < 0) {
@@ -257,34 +259,41 @@ static int run_test(struct test *test, int subtest)
         }
 
         if (!child) {
-                pr_debug("test child forked, pid %d\n", getpid());
-                if (!verbose) {
-                        int nullfd = open("/dev/null", O_WRONLY);
-                        if (nullfd >= 0) {
-                                close(STDERR_FILENO);
-                                close(STDOUT_FILENO);
-
-                                dup2(nullfd, STDOUT_FILENO);
-                                dup2(STDOUT_FILENO, STDERR_FILENO);
-                                close(nullfd);
+                if (!dont_fork) {
+                        pr_debug("test child forked, pid %d\n", getpid());
+
+                        if (!verbose) {
+                                int nullfd = open("/dev/null", O_WRONLY);
+
+                                if (nullfd >= 0) {
+                                        close(STDERR_FILENO);
+                                        close(STDOUT_FILENO);
+
+                                        dup2(nullfd, STDOUT_FILENO);
+                                        dup2(STDOUT_FILENO, STDERR_FILENO);
+                                        close(nullfd);
+                                }
+                        } else {
+                                signal(SIGSEGV, sighandler_dump_stack);
+                                signal(SIGFPE, sighandler_dump_stack);
                         }
-                } else {
-                        signal(SIGSEGV, sighandler_dump_stack);
-                        signal(SIGFPE, sighandler_dump_stack);
                 }
 
                 err = test->func(subtest);
-                exit(err);
+                if (!dont_fork)
+                        exit(err);
         }
 
-        wait(&status);
+        if (!dont_fork) {
+                wait(&status);
 
-        if (WIFEXITED(status)) {
-                err = (signed char)WEXITSTATUS(status);
-                pr_debug("test child finished with %d\n", err);
-        } else if (WIFSIGNALED(status)) {
-                err = -1;
-                pr_debug("test child interrupted\n");
+                if (WIFEXITED(status)) {
+                        err = (signed char)WEXITSTATUS(status);
+                        pr_debug("test child finished with %d\n", err);
+                } else if (WIFSIGNALED(status)) {
+                        err = -1;
+                        pr_debug("test child interrupted\n");
+                }
         }
 
         return err;
@@ -425,6 +434,8 @@ int cmd_test(int argc, const char **argv, const char *prefix __maybe_unused)
         OPT_STRING('s', "skip", &skip, "tests", "tests to skip"),
         OPT_INCR('v', "verbose", &verbose,
                     "be more verbose (show symbol address, etc)"),
+        OPT_BOOLEAN('F', "dont-fork", &dont_fork,
+                    "Do not fork for testcase"),
         OPT_END()
         };
         const char * const test_subcommands[] = { "list", NULL };