From: David Marchand <david.marchand@redhat.com>
To: dev@dpdk.org
Cc: aconole@redhat.com, stable@dpdk.org
Subject: [dpdk-stable] [PATCH v2] test/common: fix log2 check
Date: Fri, 20 Dec 2019 15:01:49 +0100 [thread overview]
Message-ID: <20191220140149.1043-1-david.marchand@redhat.com> (raw)
In-Reply-To: <20191204205241.5691-1-david.marchand@redhat.com>
We recently started to get random failures on the common_autotest ut with
clang on Ubuntu 16.04.6.
Example: https://travis-ci.com/DPDK/dpdk/jobs/263177424
Wrong rte_log2_u64(0) val 0, expected ffffffff
Test Failed
The ut passes 0 to log2() to get an expected value.
Quoting log2 / log(3) manual:
If x is zero, then a pole error occurs, and the functions return
-HUGE_VAL, -HUGE_VALF, or -HUGE_VALL, respectively.
rte_log2_uXX helpers handle 0 as a special value and return 0.
Let's have dedicated tests for this case.
Fixes: 05c4345ef5c2 ("test: add unit test for integer log2 function")
Cc: stable@dpdk.org
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Aaron Conole <aconole@redhat.com>
---
Changelog since v1:
- added comment in rte_log2_uXX API descriptions,
---
app/test/test_common.c | 14 +++++++++++++-
lib/librte_eal/common/include/rte_common.h | 6 ++++++
2 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/app/test/test_common.c b/app/test/test_common.c
index 2b856f8ba5..12bd1cad90 100644
--- a/app/test/test_common.c
+++ b/app/test/test_common.c
@@ -216,7 +216,19 @@ test_log2(void)
const uint32_t max = 0x10000;
const uint32_t step = 1;
- for (i = 0; i < max; i = i + step) {
+ compare = rte_log2_u32(0);
+ if (compare != 0) {
+ printf("Wrong rte_log2_u32(0) val %x, expected 0\n", compare);
+ return TEST_FAILED;
+ }
+
+ compare = rte_log2_u64(0);
+ if (compare != 0) {
+ printf("Wrong rte_log2_u64(0) val %x, expected 0\n", compare);
+ return TEST_FAILED;
+ }
+
+ for (i = 1; i < max; i = i + step) {
uint64_t i64;
/* extend range for 64-bit */
diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index 459d082d14..7a98071ffe 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -538,6 +538,9 @@ rte_bsf32_safe(uint64_t v, uint32_t *pos)
/**
* Return the rounded-up log2 of a integer.
*
+ * @note Contrary to the logarithm mathematical operation,
+ * rte_log2_u32(0) == 0 and not -inf.
+ *
* @param v
* The input parameter.
* @return
@@ -632,6 +635,9 @@ rte_fls_u64(uint64_t x)
/**
* Return the rounded-up log2 of a 64-bit integer.
*
+ * @note Contrary to the logarithm mathematical operation,
+ * rte_log2_u32(0) == 0 and not -inf.
+ *
* @param v
* The input parameter.
* @return
--
2.23.0
next prev parent reply other threads:[~2019-12-20 14:02 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-04 20:52 [dpdk-stable] [PATCH] " David Marchand
2019-12-04 21:19 ` Aaron Conole
2019-12-05 8:31 ` David Marchand
2019-12-05 14:39 ` Aaron Conole
2019-12-20 14:01 ` David Marchand [this message]
2019-12-20 14:06 ` [dpdk-stable] [PATCH v2] " David Marchand
2019-12-20 14:43 ` David Marchand
2019-12-20 14:52 ` Aaron Conole
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