From 776b194116d1a484b6d04abfe4b86272f0700144 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 12 Dec 2024 10:56:20 -0800 Subject: [PATCH] clocksource/wdtest: Print time values for short udelay(1) When a pair of clocksource reads separated by a udelay(1) claim less than a full microsecond of elapsed time, print the measured delay as part of the splat. Signed-off-by: Paul E. McKenney Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/717a2ddf-a80f-490b-aa3a-4e4b74fa56ca@paulmck-laptop --- kernel/time/clocksource-wdtest.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/time/clocksource-wdtest.c b/kernel/time/clocksource-wdtest.c index 62e73444ffe4..38dae590b29f 100644 --- a/kernel/time/clocksource-wdtest.c +++ b/kernel/time/clocksource-wdtest.c @@ -137,7 +137,8 @@ static int wdtest_func(void *arg) udelay(1); j2 = clocksource_wdtest_ktime.read(&clocksource_wdtest_ktime); pr_info("--- tsc-like times: %lu - %lu = %lu.\n", j2, j1, j2 - j1); - WARN_ON_ONCE(time_before(j2, j1 + NSEC_PER_USEC)); + WARN_ONCE(time_before(j2, j1 + NSEC_PER_USEC), + "Expected at least 1000ns, got %lu.\n", j2 - j1); /* Verify tsc-like stability with various numbers of errors injected. */ max_retries = clocksource_get_max_watchdog_retry(); -- 2.25.1