From: Keith Busch <keith.busch@xxxxxxxxx> Subject: 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@xxxxxxxxxxxxxxxxxxxx: add expansion to struct gup_benchmark for future use] Link: http://lkml.kernel.org/r/20181010195605.10689-1-keith.busch@xxxxxxxxx Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/gup_benchmark.c | 9 +++++++-- tools/testing/selftests/vm/gup_benchmark.c | 6 ++++-- 2 files changed, 11 insertions(+), 4 deletions(-) --- a/mm/gup_benchmark.c~mm-gup_benchmark-time-put_page +++ a/mm/gup_benchmark.c @@ -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(unsigne } 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; --- a/tools/testing/selftests/vm/gup_benchmark.c~mm-gup_benchmark-time-put_page +++ a/tools/testing/selftests/vm/gup_benchmark.c @@ -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"); _
