ltp: backport clock_gettime04 fix from upstream

This is to get rid of the intermittent failures in clock_gettime04,
which are likely caused by different clock tick rates on platforms.
Here give two thresholds (in milliseconds) for comparison, one for
COARSE clock and one for the rest.

(From OE-Core rev: 9452efd99299a5bf23cc6518e8900e58b3a2fff9)

Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 90 insertions, 0 deletions

diff --git a/meta/recipes-extended/ltp/ltp/0001-clock_gettime04-set-threshold-based-on-the-clock-res.patch b/meta/recipes-extended/ltp/ltp/0001-clock_gettime04-set-threshold-based-on-the-clock-res.patch
new file mode 100644
index 0000000000..b4879221ad
--- /dev/null
+++ b/meta/recipes-extended/ltp/ltp/0001-clock_gettime04-set-threshold-based-on-the-clock-res.patch
@@ -0,0 +1,89 @@
+From 9851deb86ef257a98d7433280161d8ca685aa669 Mon Sep 17 00:00:00 2001
+From: Li Wang <liwang@redhat.com>
+Date: Tue, 29 Mar 2022 13:03:51 +0800
+Subject: [PATCH] clock_gettime04: set threshold based on the clock resolution
+
+This is to get rid of the intermittent failures in clock_gettime04,
+which are likely caused by different clock tick rates on platforms.
+Here give two thresholds (in milliseconds) for comparison, one for
+COARSE clock and one for the rest.
+
+Error log:
+  clock_gettime04.c:163: TFAIL: CLOCK_REALTIME_COARSE(syscall with old kernel spec):
+        Difference between successive readings greater than 5 ms (1): 10
+  clock_gettime04.c:163: TFAIL: CLOCK_MONOTONIC_COARSE(vDSO with old kernel spec):
+        Difference between successive readings greater than 5 ms (2): 10
+
+From Waiman Long:
+  That failure happens for CLOCK_REALTIME_COARSE which is a faster but less
+  precise version of CLOCK_REALTIME. The time resolution is actually a clock
+  tick. Since arm64 has a HZ rate of 100. That means each tick is 10ms. So a
+  CLOCK_REALTIME_COARSE threshold of 5ms is probably not enough. I would say
+  in the case of CLOCK_REALTIME_COARSE, we have to increase the threshold based
+  on the clock tick rate of the system. This is more a test failure than is
+  an inherent problem in the kernel.
+
+Fixes #898
+
+Upstream-Status: Backport
+[https://github.com/linux-test-project/ltp/commit/9851deb86ef257a98d7433280161d8ca685aa669]
+
+Reported-by: Eirik Fuller <efuller@redhat.com>
+Signed-off-by: Li Wang <liwang@redhat.com>
+Cc: Waiman Long <llong@redhat.com>
+Cc: Viresh Kumar <viresh.kumar@linaro.org>
+Reviewed-by: Cyril Hrubis <chrubis@suse.cz>
+Acked-by: Waiman Long <longman@redhat.com>
+Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
+---
+ .../syscalls/clock_gettime/clock_gettime04.c   | 18 ++++++++++++++++--
+ 1 file changed, 16 insertions(+), 2 deletions(-)
+
+diff --git a/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c b/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c
+index a8d2c5b38..c279da79e 100644
+--- a/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c
++++ b/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c
+@@ -35,7 +35,7 @@ clockid_t clks[] = {
+ };
+ 
+ static gettime_t ptr_vdso_gettime, ptr_vdso_gettime64;
+-static long long delta = 5;
++static long long delta, precise_delta, coarse_delta;
+ 
+ static inline int do_vdso_gettime(gettime_t vdso, clockid_t clk_id, void *ts)
+ {
+@@ -92,9 +92,18 @@ static struct time64_variants variants[] = {
+ 
+ static void setup(void)
+ {
++       struct timespec res;
++
++       clock_getres(CLOCK_REALTIME, &res);
++       precise_delta = 5 + res.tv_nsec / 1000000;
++
++       clock_getres(CLOCK_REALTIME_COARSE, &res);
++       coarse_delta = 5 + res.tv_nsec / 1000000;
++
+        if (tst_is_virt(VIRT_ANY)) {
+                tst_res(TINFO, "Running in a virtual machine, multiply the delta by 10.");
+-               delta *= 10;
++               precise_delta *= 10;
++               coarse_delta *= 10;
+        }
+ 
+        find_clock_gettime_vdso(&ptr_vdso_gettime, &ptr_vdso_gettime64);
+@@ -108,6 +117,11 @@ static void run(unsigned int i)
+        int count = 10000, ret;
+        unsigned int j;
+ 
++       if (clks[i] == CLOCK_REALTIME_COARSE || clks[i] == CLOCK_MONOTONIC_COARSE)
++               delta = coarse_delta;
++       else
++               delta = precise_delta;
++
+        do {
+                for (j = 0; j < ARRAY_SIZE(variants); j++) {
+                        /* Refresh time in start */
+-- 
+2.34.1
+
diff --git a/meta/recipes-extended/ltp/ltp_20220121.bb b/meta/recipes-extended/ltp/ltp_20220121.bb
index 4ae54492f3..51e8db4f1e 100644
--- a/meta/recipes-extended/ltp/ltp_20220121.bb
+++ b/meta/recipes-extended/ltp/ltp_20220121.bb
@@ -29,6 +29,7 @@ SRC_URI = "git://github.com/linux-test-project/ltp.git;branch=master;protocol=ht
            file://0001-metadata-parse.sh-sort-filelist-for-reproducibility.patch \
            file://disable_hanging_tests.patch \
            file://0001-syscalls-pread02-extend-buffer-to-avoid-glibc-overflow-detection.patch \
+           file://0001-clock_gettime04-set-threshold-based-on-the-clock-res.patch \
            "
 
 S = "${WORKDIR}/git"