KVM: selftests: Rework timespec functions and usage

The steal_time test's timespec stop condition was wrong and should have
used the timespec functions instead to avoid being wrong, but
timespec_diff had a strange interface. Rework all the timespec API and
its use.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
index d82f7bc..360cd3e 100644 (file)
--- a/tools/testing/selftests/kvm/demand_paging_test.c
+++ b/tools/testing/selftests/kvm/demand_paging_test.c
@@ -117,8 +117,7 @@ static void *vcpu_worker(void *data)
        struct kvm_vm *vm = args->vm;
        int vcpu_id = args->vcpu_id;
        struct kvm_run *run;
-       struct timespec start;
-       struct timespec end;
+       struct timespec start, end, ts_diff;
 
        vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
        run = vcpu_state(vm, vcpu_id);
@@ -135,9 +134,9 @@ static void *vcpu_worker(void *data)
        }
 
        clock_gettime(CLOCK_MONOTONIC, &end);
-       PER_VCPU_DEBUG("vCPU %d execution time: %lld.%.9lds\n", vcpu_id,
-                      (long long)(timespec_diff(start, end).tv_sec),
-                      timespec_diff(start, end).tv_nsec);
+       ts_diff = timespec_sub(end, start);
+       PER_VCPU_DEBUG("vCPU %d execution time: %ld.%.9lds\n", vcpu_id,
+                      ts_diff.tv_sec, ts_diff.tv_nsec);
 
        return NULL;
 }
@@ -201,8 +200,8 @@ static int handle_uffd_page_request(int uffd, uint64_t addr)
 
        clock_gettime(CLOCK_MONOTONIC, &end);
 
-       PER_PAGE_DEBUG("UFFDIO_COPY %d \t%lld ns\n", tid,
-                      (long long)timespec_to_ns(timespec_diff(start, end)));
+       PER_PAGE_DEBUG("UFFDIO_COPY %d \t%ld ns\n", tid,
+                      timespec_to_ns(timespec_sub(end, start)));
        PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n",
                       host_page_size, addr, tid);
 
@@ -224,8 +223,7 @@ static void *uffd_handler_thread_fn(void *arg)
        int pipefd = uffd_args->pipefd;
        useconds_t delay = uffd_args->delay;
        int64_t pages = 0;
-       struct timespec start;
-       struct timespec end;
+       struct timespec start, end, ts_diff;
 
        clock_gettime(CLOCK_MONOTONIC, &start);
        while (!quit_uffd_thread) {
@@ -295,11 +293,10 @@ static void *uffd_handler_thread_fn(void *arg)
        }
 
        clock_gettime(CLOCK_MONOTONIC, &end);
-       PER_VCPU_DEBUG("userfaulted %ld pages over %lld.%.9lds. (%f/sec)\n",
-                      pages, (long long)(timespec_diff(start, end).tv_sec),
-                      timespec_diff(start, end).tv_nsec, pages /
-                      ((double)timespec_diff(start, end).tv_sec +
-                       (double)timespec_diff(start, end).tv_nsec / 100000000.0));
+       ts_diff = timespec_sub(end, start);
+       PER_VCPU_DEBUG("userfaulted %ld pages over %ld.%.9lds. (%f/sec)\n",
+                      pages, ts_diff.tv_sec, ts_diff.tv_nsec,
+                      pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
 
        return NULL;
 }
@@ -360,13 +357,12 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd,
        pthread_t *vcpu_threads;
        pthread_t *uffd_handler_threads = NULL;
        struct uffd_handler_args *uffd_args = NULL;
+       struct timespec start, end, ts_diff;
        int *pipefds = NULL;
        struct kvm_vm *vm;
        uint64_t guest_num_pages;
        int vcpu_id;
        int r;
-       struct timespec start;
-       struct timespec end;
 
        vm = create_vm(mode, vcpus, vcpu_memory_bytes);
 
@@ -514,12 +510,11 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd,
                }
        }
 
-       pr_info("Total guest execution time: %lld.%.9lds\n",
-               (long long)(timespec_diff(start, end).tv_sec),
-               timespec_diff(start, end).tv_nsec);
+       ts_diff = timespec_sub(end, start);
+       pr_info("Total guest execution time: %ld.%.9lds\n",
+               ts_diff.tv_sec, ts_diff.tv_nsec);
        pr_info("Overall demand paging rate: %f pgs/sec\n",
-               guest_num_pages / ((double)timespec_diff(start, end).tv_sec +
-               (double)timespec_diff(start, end).tv_nsec / 100000000.0));
+               guest_num_pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
 
        ucall_uninit(vm);
        kvm_vm_free(vm);

diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
index f588ad1..5eb01bf 100644 (file)
--- a/tools/testing/selftests/kvm/include/test_util.h
+++ b/tools/testing/selftests/kvm/include/test_util.h
@@ -61,7 +61,8 @@ void test_assert(bool exp, const char *exp_str,
 size_t parse_size(const char *size);
 
 int64_t timespec_to_ns(struct timespec ts);
-struct timespec timespec_diff(struct timespec start, struct timespec end);
 struct timespec timespec_add_ns(struct timespec ts, int64_t ns);
+struct timespec timespec_add(struct timespec ts1, struct timespec ts2);
+struct timespec timespec_sub(struct timespec ts1, struct timespec ts2);
 
 #endif /* SELFTEST_KVM_TEST_UTIL_H */

diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
index ee12c4b..689e97c 100644 (file)
--- a/tools/testing/selftests/kvm/lib/test_util.c
+++ b/tools/testing/selftests/kvm/lib/test_util.c
@@ -56,36 +56,31 @@ int64_t timespec_to_ns(struct timespec ts)
        return (int64_t)ts.tv_nsec + 1000000000LL * (int64_t)ts.tv_sec;
 }
 
-struct timespec timespec_diff(struct timespec start, struct timespec end)
-{
-       struct timespec temp;
-
-       if ((end.tv_nsec - start.tv_nsec) < 0) {
-               temp.tv_sec = end.tv_sec - start.tv_sec - 1;
-               temp.tv_nsec = 1000000000LL + end.tv_nsec - start.tv_nsec;
-       } else {
-               temp.tv_sec = end.tv_sec - start.tv_sec;
-               temp.tv_nsec = end.tv_nsec - start.tv_nsec;
-       }
-
-       return temp;
-}
-
 struct timespec timespec_add_ns(struct timespec ts, int64_t ns)
 {
        struct timespec res;
 
-       res.tv_sec = ts.tv_sec;
        res.tv_nsec = ts.tv_nsec + ns;
-
-       if (res.tv_nsec > 1000000000UL) {
-               res.tv_sec += 1;
-               res.tv_nsec -= 1000000000UL;
-       }
+       res.tv_sec = ts.tv_sec + res.tv_nsec / 1000000000LL;
+       res.tv_nsec %= 1000000000LL;
 
        return res;
 }
 
+struct timespec timespec_add(struct timespec ts1, struct timespec ts2)
+{
+       int64_t ns1 = timespec_to_ns(ts1);
+       int64_t ns2 = timespec_to_ns(ts2);
+       return timespec_add_ns((struct timespec){0}, ns1 + ns2);
+}
+
+struct timespec timespec_sub(struct timespec ts1, struct timespec ts2)
+{
+       int64_t ns1 = timespec_to_ns(ts1);
+       int64_t ns2 = timespec_to_ns(ts2);
+       return timespec_add_ns((struct timespec){0}, ns1 - ns2);
+}
+
 void print_skip(const char *fmt, ...)
 {
        va_list ap;

diff --git a/tools/testing/selftests/kvm/steal_time.c b/tools/testing/selftests/kvm/steal_time.c
index f976ac5..fcc8400 100644 (file)
--- a/tools/testing/selftests/kvm/steal_time.c
+++ b/tools/testing/selftests/kvm/steal_time.c
@@ -242,7 +242,7 @@ static void *do_steal_time(void *arg)
 
        while (1) {
                clock_gettime(CLOCK_MONOTONIC, &ts);
-               if (ts.tv_sec > stop.tv_sec || ts.tv_nsec >= stop.tv_nsec)
+               if (timespec_to_ns(timespec_sub(ts, stop)) >= 0)
                        break;
        }