Commit 26db3d09 authored by Keith Busch's avatar Keith Busch Committed by Linus Torvalds
Browse files

mm/gup_benchmark.c: time put_page() 

We'd like to measure time to unpin user pages, so this adds a second
benchmark timer on put_page, separate from get_page.

Adding the field breaks this ioctl ABI, but should be okay since this an
in-tree kernel selftest.

[akpm@linux-foundation.org: add expansion to struct gup_benchmark for future use]
Link: http://lkml.kernel.org/r/20181010195605.10689-1-keith.busch@intel.com


Signed-off-by: default avatarKeith Busch <keith.busch@intel.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7a1adfdd

mm/gup_benchmark.c

+7 −2
Original line number Diff line number Diff line
@@ -8,11 +8,13 @@ 
#define GUP_FAST_BENCHMARK	_IOWR('g', 1, struct gup_benchmark)



struct gup_benchmark {

	__u64 delta_usec;

	__u64 get_delta_usec;

	__u64 put_delta_usec;

	__u64 addr;

	__u64 size;

	__u32 nr_pages_per_call;

	__u32 flags;

	__u64 expansion[10];	/* For future use */

};



static int __gup_benchmark_ioctl(unsigned int cmd,
@@ -48,14 +50,17 @@ static int __gup_benchmark_ioctl(unsigned int cmd, 
	}

	end_time = ktime_get();



	gup->delta_usec = ktime_us_delta(end_time, start_time);

	gup->get_delta_usec = ktime_us_delta(end_time, start_time);

	gup->size = addr - gup->addr;



	start_time = ktime_get();

	for (i = 0; i < nr_pages; i++) {

		if (!pages[i])

			break;

		put_page(pages[i]);

	}

	end_time = ktime_get();

	gup->put_delta_usec = ktime_us_delta(end_time, start_time);



	kvfree(pages);

	return 0;

tools/testing/selftests/vm/gup_benchmark.c

+4 −2
Original line number Diff line number Diff line
@@ -17,7 +17,8 @@ 
#define GUP_FAST_BENCHMARK	_IOWR('g', 1, struct gup_benchmark)



struct gup_benchmark {

	__u64 delta_usec;

	__u64 get_delta_usec;

	__u64 put_delta_usec;

	__u64 addr;

	__u64 size;

	__u32 nr_pages_per_call;
@@ -81,7 +82,8 @@ int main(int argc, char **argv) 
		if (ioctl(fd, GUP_FAST_BENCHMARK, &gup))

			perror("ioctl"), exit(1);



		printf("Time: %lld us", gup.delta_usec);

		printf("Time: get:%lld put:%lld us", gup.get_delta_usec,

			gup.put_delta_usec);

		if (gup.size != size)

			printf(", truncated (size: %lld)", gup.size);

		printf("\n");

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