Add a test of the speed and memory use of string_stream.
string_stream_performance_test() doesn't actually "test" anything (it cannot fail unless the system has run out of allocatable memory) but it measures the speed and memory consumption of the string_stream and reports the result.
This allows changes in the string_stream implementation to be compared.
Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com Reviewed-by: David Gow davidgow@google.com --- lib/kunit/string-stream-test.c | 54 ++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+)
diff --git a/lib/kunit/string-stream-test.c b/lib/kunit/string-stream-test.c index b759974d9cec..06822766f29a 100644 --- a/lib/kunit/string-stream-test.c +++ b/lib/kunit/string-stream-test.c @@ -8,7 +8,9 @@
#include <kunit/static_stub.h> #include <kunit/test.h> +#include <linux/ktime.h> #include <linux/slab.h> +#include <linux/timekeeping.h>
#include "string-stream.h"
@@ -454,6 +456,57 @@ static void string_stream_auto_newline_test(struct kunit *test) "One\nTwo\nThree\nFour\nFive\nSix\nSeven\n\nEight\n"); }
+/* + * This doesn't actually "test" anything. It reports time taken + * and memory used for logging a large number of lines. + */ +static void string_stream_performance_test(struct kunit *test) +{ + struct string_stream_fragment *frag_container; + struct string_stream *stream; + char test_line[101]; + ktime_t start_time, end_time; + size_t len, bytes_requested, actual_bytes_used, total_string_length; + int offset, i; + + stream = kunit_alloc_string_stream(test, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream); + + memset(test_line, 'x', sizeof(test_line) - 1); + test_line[sizeof(test_line) - 1] = '\0'; + + start_time = ktime_get(); + for (i = 0; i < 10000; i++) { + offset = i % (sizeof(test_line) - 1); + string_stream_add(stream, "%s: %d\n", &test_line[offset], i); + } + end_time = ktime_get(); + + /* + * Calculate memory used. This doesn't include invisible + * overhead due to kernel allocator fragment size rounding. + */ + bytes_requested = sizeof(*stream); + actual_bytes_used = ksize(stream); + total_string_length = 0; + + list_for_each_entry(frag_container, &stream->fragments, node) { + bytes_requested += sizeof(*frag_container); + actual_bytes_used += ksize(frag_container); + + len = strlen(frag_container->fragment); + total_string_length += len; + bytes_requested += len + 1; /* +1 for '\0' */ + actual_bytes_used += ksize(frag_container->fragment); + } + + kunit_info(test, "Time elapsed: %lld us\n", + ktime_us_delta(end_time, start_time)); + kunit_info(test, "Total string length: %zu\n", total_string_length); + kunit_info(test, "Bytes requested: %zu\n", bytes_requested); + kunit_info(test, "Actual bytes allocated: %zu\n", actual_bytes_used); +} + static int string_stream_test_init(struct kunit *test) { struct string_stream_test_priv *priv; @@ -479,6 +532,7 @@ static struct kunit_case string_stream_test_cases[] = { KUNIT_CASE(string_stream_append_empty_string_test), KUNIT_CASE(string_stream_no_auto_newline_test), KUNIT_CASE(string_stream_auto_newline_test), + KUNIT_CASE(string_stream_performance_test), {} };