Re: [RFC PATCH v2 2/7] KVM: selftests: Use flag CLOCK_MONOTONIC_RAW for timing
From: Andrew Jones
Date: Thu Feb 25 2021 - 13:56:37 EST
On Thu, Feb 25, 2021 at 01:59:35PM +0800, Yanan Wang wrote:
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In addition to function of CLOCK_MONOTONIC, flag CLOCK_MONOTONIC_RAW can
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also shield possiable impact of NTP, which can provide more robustness.
IIRC, this should include
Suggested-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
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Signed-off-by: Yanan Wang <wangyanan55@xxxxxxxxxx>
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---
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tools/testing/selftests/kvm/demand_paging_test.c | 8 ++++----
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tools/testing/selftests/kvm/dirty_log_perf_test.c | 14 +++++++-------
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tools/testing/selftests/kvm/lib/test_util.c | 2 +-
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tools/testing/selftests/kvm/steal_time.c | 4 ++--
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4 files changed, 14 insertions(+), 14 deletions(-)
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diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
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index 5f7a229c3af1..efbf0c1e9130 100644
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--- a/tools/testing/selftests/kvm/demand_paging_test.c
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+++ b/tools/testing/selftests/kvm/demand_paging_test.c
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@@ -53,7 +53,7 @@ static void *vcpu_worker(void *data)
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vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
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run = vcpu_state(vm, vcpu_id);
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- clock_gettime(CLOCK_MONOTONIC, &start);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &start);
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/* Let the guest access its memory */
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ret = _vcpu_run(vm, vcpu_id);
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@@ -86,7 +86,7 @@ static int handle_uffd_page_request(int uffd, uint64_t addr)
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copy.len = perf_test_args.host_page_size;
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copy.mode = 0;
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- clock_gettime(CLOCK_MONOTONIC, &start);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &start);
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r = ioctl(uffd, UFFDIO_COPY, ©);
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if (r == -1) {
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@@ -123,7 +123,7 @@ static void *uffd_handler_thread_fn(void *arg)
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struct timespec start;
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struct timespec ts_diff;
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- clock_gettime(CLOCK_MONOTONIC, &start);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &start);
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while (!quit_uffd_thread) {
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struct uffd_msg msg;
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struct pollfd pollfd[2];
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@@ -336,7 +336,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
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pr_info("Finished creating vCPUs and starting uffd threads\n");
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- clock_gettime(CLOCK_MONOTONIC, &start);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &start);
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for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
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pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
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diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c
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index 04a2641261be..6cff4ccf9525 100644
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--- a/tools/testing/selftests/kvm/dirty_log_perf_test.c
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+++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c
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@@ -50,7 +50,7 @@ static void *vcpu_worker(void *data)
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while (!READ_ONCE(host_quit)) {
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int current_iteration = READ_ONCE(iteration);
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- clock_gettime(CLOCK_MONOTONIC, &start);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &start);
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ret = _vcpu_run(vm, vcpu_id);
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ts_diff = timespec_elapsed(start);
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@@ -141,7 +141,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
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iteration = 0;
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host_quit = false;
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- clock_gettime(CLOCK_MONOTONIC, &start);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &start);
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for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
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vcpu_last_completed_iteration[vcpu_id] = -1;
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@@ -162,7 +162,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
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ts_diff.tv_sec, ts_diff.tv_nsec);
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/* Enable dirty logging */
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- clock_gettime(CLOCK_MONOTONIC, &start);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &start);
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vm_mem_region_set_flags(vm, PERF_TEST_MEM_SLOT_INDEX,
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KVM_MEM_LOG_DIRTY_PAGES);
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ts_diff = timespec_elapsed(start);
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@@ -174,7 +174,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
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* Incrementing the iteration number will start the vCPUs
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* dirtying memory again.
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*/
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- clock_gettime(CLOCK_MONOTONIC, &start);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &start);
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iteration++;
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pr_debug("Starting iteration %d\n", iteration);
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@@ -189,7 +189,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
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pr_info("Iteration %d dirty memory time: %ld.%.9lds\n",
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iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
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- clock_gettime(CLOCK_MONOTONIC, &start);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &start);
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kvm_vm_get_dirty_log(vm, PERF_TEST_MEM_SLOT_INDEX, bmap);
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ts_diff = timespec_elapsed(start);
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@@ -199,7 +199,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
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iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
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if (dirty_log_manual_caps) {
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- clock_gettime(CLOCK_MONOTONIC, &start);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &start);
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kvm_vm_clear_dirty_log(vm, PERF_TEST_MEM_SLOT_INDEX, bmap, 0,
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host_num_pages);
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@@ -212,7 +212,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
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}
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/* Disable dirty logging */
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- clock_gettime(CLOCK_MONOTONIC, &start);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &start);
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vm_mem_region_set_flags(vm, PERF_TEST_MEM_SLOT_INDEX, 0);
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ts_diff = timespec_elapsed(start);
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pr_info("Disabling dirty logging time: %ld.%.9lds\n",
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diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
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index 906c955384e2..c7c0627c6842 100644
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--- a/tools/testing/selftests/kvm/lib/test_util.c
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+++ b/tools/testing/selftests/kvm/lib/test_util.c
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@@ -89,7 +89,7 @@ struct timespec timespec_elapsed(struct timespec start)
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{
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struct timespec end;
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- clock_gettime(CLOCK_MONOTONIC, &end);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &end);
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return timespec_sub(end, start);
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}
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diff --git a/tools/testing/selftests/kvm/steal_time.c b/tools/testing/selftests/kvm/steal_time.c
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index fcc840088c91..5bc582d3f2a2 100644
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--- a/tools/testing/selftests/kvm/steal_time.c
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+++ b/tools/testing/selftests/kvm/steal_time.c
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@@ -237,11 +237,11 @@ static void *do_steal_time(void *arg)
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{
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struct timespec ts, stop;
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- clock_gettime(CLOCK_MONOTONIC, &ts);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
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stop = timespec_add_ns(ts, MIN_RUN_DELAY_NS);
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while (1) {
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- clock_gettime(CLOCK_MONOTONIC, &ts);
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+ clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
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if (timespec_to_ns(timespec_sub(ts, stop)) >= 0)
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break;
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}
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--
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2.19.1
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