perf tests: Add test for perf_evlist__filter_pollfd()

That will use a synthetic evlist with just what is touched by this new
method to check that it works as expected.

Output in verbose mode:

  $ perf test -v pollfd
  33: Filter fds with revents mask in a pollfd array         :
  --- start ---
  filtering all but pollfd[2]:
  before:   5 [ 5, 4, 3, 2, 1 ]
   after:   1 [ 3 ]
  filtering all but (pollfd[0], pollfd[3]):
  before:   5 [ 5, 4, 3, 2, 1 ]
   after:   2 [ 5, 2 ]
  test child finished with 0
  ---- end ----
  Filter fds with revents mask in a pollfd array: Ok
  $

Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-x7c8liszdvc3ocmanf2cet8p@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Makefile.perf

@@ -400,6 +400,7 @@ LIB_OBJS += $(OUTPUT)tests/open-syscall-tp-fields.o
 LIB_OBJS += $(OUTPUT)tests/mmap-basic.o
 LIB_OBJS += $(OUTPUT)tests/perf-record.o
 LIB_OBJS += $(OUTPUT)tests/rdpmc.o
+LIB_OBJS += $(OUTPUT)tests/evlist.o
 LIB_OBJS += $(OUTPUT)tests/evsel-roundtrip-name.o
 LIB_OBJS += $(OUTPUT)tests/evsel-tp-sched.o
 LIB_OBJS += $(OUTPUT)tests/pmu.o

tools/perf/tests/builtin-test.c

@@ -157,6 +157,10 @@ static struct test {
 		.desc = "Test tracking with sched_switch",
 		.func = test__switch_tracking,
 	},
+	{
+		.desc = "Filter fds with revents mask in a pollfd array",
+		.func = test__perf_evlist__filter_pollfd,
+	},
 	{
 		.func = NULL,
 	},

tools/perf/tests/evlist.c

@@ -0,0 +1,103 @@
+#include "util/evlist.h"
+#include "util/debug.h"
+#include "tests/tests.h"
+
+static void perf_evlist__init_pollfd(struct perf_evlist *evlist,
+				     int nr_fds_alloc, short revents)
+{
+	int fd;
+
+	evlist->nr_fds = nr_fds_alloc;
+
+	for (fd = 0; fd < nr_fds_alloc; ++fd) {
+		evlist->pollfd[fd].fd	   = nr_fds_alloc - fd;
+		evlist->pollfd[fd].revents = revents;
+	}
+}
+
+static int perf_evlist__fprintf_pollfd(struct perf_evlist *evlist,
+				       const char *prefix, FILE *fp)
+{
+	int printed = 0, fd;
+
+	if (!verbose)
+		return 0;
+
+	printed += fprintf(fp, "\n%s: %3d [ ", prefix, evlist->nr_fds);
+	for (fd = 0; fd < evlist->nr_fds; ++fd)
+		printed += fprintf(fp, "%s%d", fd ? ", " : "", evlist->pollfd[fd].fd);
+	printed += fprintf(fp, " ]");
+	return printed;
+}
+
+int test__perf_evlist__filter_pollfd(void)
+{
+	const int nr_fds_alloc = 5;
+	int nr_fds, expected_fd[2], fd;
+	struct pollfd pollfd[nr_fds_alloc];
+	struct perf_evlist evlist_alloc = {
+		.pollfd	= pollfd,
+	}, *evlist = &evlist_alloc;
+
+	perf_evlist__init_pollfd(evlist, nr_fds_alloc, POLLIN);
+	nr_fds = perf_evlist__filter_pollfd(evlist, POLLHUP);
+	if (nr_fds != nr_fds_alloc) {
+		pr_debug("\nperf_evlist__filter_pollfd()=%d != %d shouldn't have filtered anything",
+			 nr_fds, nr_fds_alloc);
+		return TEST_FAIL;
+	}
+
+	perf_evlist__init_pollfd(evlist, nr_fds_alloc, POLLHUP);
+	nr_fds = perf_evlist__filter_pollfd(evlist, POLLHUP);
+	if (nr_fds != 0) {
+		pr_debug("\nperf_evlist__filter_pollfd()=%d != %d, should have filtered all fds",
+			 nr_fds, nr_fds_alloc);
+		return TEST_FAIL;
+	}
+
+	perf_evlist__init_pollfd(evlist, nr_fds_alloc, POLLHUP);
+	pollfd[2].revents = POLLIN;
+	expected_fd[0] = pollfd[2].fd;
+
+	pr_debug("\nfiltering all but pollfd[2]:");
+	perf_evlist__fprintf_pollfd(evlist, "before", stderr);
+	nr_fds = perf_evlist__filter_pollfd(evlist, POLLHUP);
+	perf_evlist__fprintf_pollfd(evlist, " after", stderr);
+	if (nr_fds != 1) {
+		pr_debug("\nperf_evlist__filter_pollfd()=%d != 1, should have left just one event",
+			 nr_fds);
+		return TEST_FAIL;
+	}
+
+	if (pollfd[0].fd != expected_fd[0]) {
+		pr_debug("\npollfd[0].fd=%d != %d\n", pollfd[0].fd, expected_fd[0]);
+		return TEST_FAIL;
+	}
+
+	perf_evlist__init_pollfd(evlist, nr_fds_alloc, POLLHUP);
+	pollfd[0].revents = POLLIN;
+	expected_fd[0] = pollfd[0].fd;
+	pollfd[3].revents = POLLIN;
+	expected_fd[1] = pollfd[3].fd;
+
+	pr_debug("\nfiltering all but (pollfd[0], pollfd[3]):");
+	perf_evlist__fprintf_pollfd(evlist, "before", stderr);
+	nr_fds = perf_evlist__filter_pollfd(evlist, POLLHUP);
+	perf_evlist__fprintf_pollfd(evlist, " after", stderr);
+	if (nr_fds != 2) {
+		pr_debug("\nperf_evlist__filter_pollfd()=%d != 2, should have left just two events",
+			 nr_fds);
+		return TEST_FAIL;
+	}
+
+	for (fd = 0; fd < 2; ++fd) {
+		if (pollfd[fd].fd != expected_fd[fd]) {
+			pr_debug("\npollfd[%d].fd=%d != %d\n", fd, pollfd[fd].fd, expected_fd[fd]);
+			return TEST_FAIL;
+		}
+	}
+
+	pr_debug("\n");
+
+	return 0;
+}

tools/perf/tests/tests.h

@@ -49,6 +49,7 @@ int test__thread_mg_share(void);
 int test__hists_output(void);
 int test__hists_cumulate(void);
 int test__switch_tracking(void);
+int test__perf_evlist__filter_pollfd(void);
 
 #if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
 #ifdef HAVE_DWARF_UNWIND_SUPPORT