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kunit: string-stream: Test performance of string_stream

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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>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
This commit is contained in:
Richard Fitzgerald 2023-08-28 11:41:11 +01:00 committed by Shuah Khan
parent 05e2006ce4
commit 53568b720c
1 changed files with 54 additions and 0 deletions
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54
lib/kunit/string-stream-test.c
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@ -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),
{}
};