[PATCHv3 1/6] mm/gup_benchmark: Time put_page

[Keith Busch]

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

Cc: Kirill Shutemov <kirill.shute...@linux.intel.com>
Cc: Dave Hansen <dave.han...@intel.com>
Cc: Dan Williams <dan.j.willi...@intel.com>
Signed-off-by: Keith Busch <keith.bu...@intel.com>
---
 mm/gup_benchmark.c                         | 8 ++++++--
 tools/testing/selftests/vm/gup_benchmark.c | 6 ++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c
index 6a473709e9b6..76cd35e477af 100644
--- a/mm/gup_benchmark.c
+++ b/mm/gup_benchmark.c
@@ -8,7 +8,8 @@
 #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;
@@ -47,14 +48,17 @@ 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;
diff --git a/tools/testing/selftests/vm/gup_benchmark.c 
b/tools/testing/selftests/vm/gup_benchmark.c
index 36df55132036..bdcb97acd0ac 100644
--- a/tools/testing/selftests/vm/gup_benchmark.c
+++ b/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");
-- 
2.14.4