[dpdk-dev] [PATCH v2] common: add 64-bit log2 function
Anatoly Burakov
anatoly.burakov at intel.com
Thu Dec 20 13:07:45 CET 2018
Add missing implementation for 64-bit log2 function, and extend
the unit test to test this new function. Also, remove duplicate
reimplementation of this function from testpmd and memalloc.
Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
app/test-pmd/testpmd.c | 17 +----------------
lib/librte_eal/common/include/rte_common.h | 18 ++++++++++++++++++
lib/librte_eal/linuxapp/eal/eal_memalloc.c | 17 +----------------
test/test/test_common.c | 20 +++++++++++++++++++-
4 files changed, 39 insertions(+), 33 deletions(-)
diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index a10bc40bb..8d584b008 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -649,28 +649,13 @@ calc_mem_size(uint32_t nb_mbufs, uint32_t mbuf_sz, size_t pgsz, size_t *out)
return 0;
}
-static inline uint32_t
-bsf64(uint64_t v)
-{
- return (uint32_t)__builtin_ctzll(v);
-}
-
-static inline uint32_t
-log2_u64(uint64_t v)
-{
- if (v == 0)
- return 0;
- v = rte_align64pow2(v);
- return bsf64(v);
-}
-
static int
pagesz_flags(uint64_t page_sz)
{
/* as per mmap() manpage, all page sizes are log2 of page size
* shifted by MAP_HUGE_SHIFT
*/
- int log2 = log2_u64(page_sz);
+ int log2 = rte_log2_u64(page_sz);
return (log2 << HUGE_SHIFT);
}
diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index 7b50b8479..7178ba1e9 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -565,6 +565,24 @@ rte_fls_u64(uint64_t x)
return (x == 0) ? 0 : 64 - __builtin_clzll(x);
}
+/**
+ * Return the rounded-up log2 of a 64-bit integer.
+ *
+ * @param v
+ * The input parameter.
+ * @return
+ * The rounded-up log2 of the input, or 0 if the input is 0.
+ */
+static inline uint32_t
+rte_log2_u64(uint64_t v)
+{
+ if (v == 0)
+ return 0;
+ v = rte_align64pow2(v);
+ /* we checked for v being 0 already, so no undefined behavior */
+ return rte_bsf64(v);
+}
+
#ifndef offsetof
/** Return the offset of a field in a structure. */
#define offsetof(TYPE, MEMBER) __builtin_offsetof (TYPE, MEMBER)
diff --git a/lib/librte_eal/linuxapp/eal/eal_memalloc.c b/lib/librte_eal/linuxapp/eal/eal_memalloc.c
index 784939566..6e6af5b06 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memalloc.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memalloc.c
@@ -208,28 +208,13 @@ get_file_size(int fd)
return st.st_size;
}
-static inline uint32_t
-bsf64(uint64_t v)
-{
- return (uint32_t)__builtin_ctzll(v);
-}
-
-static inline uint32_t
-log2_u64(uint64_t v)
-{
- if (v == 0)
- return 0;
- v = rte_align64pow2(v);
- return bsf64(v);
-}
-
static int
pagesz_flags(uint64_t page_sz)
{
/* as per mmap() manpage, all page sizes are log2 of page size
* shifted by MAP_HUGE_SHIFT
*/
- int log2 = log2_u64(page_sz);
+ int log2 = rte_log2_u64(page_sz);
return log2 << RTE_MAP_HUGE_SHIFT;
}
diff --git a/test/test/test_common.c b/test/test/test_common.c
index f6dd4c18d..94d367471 100644
--- a/test/test/test_common.c
+++ b/test/test/test_common.c
@@ -213,13 +213,31 @@ test_log2(void)
const uint32_t step = 1;
for (i = 0; i < max; i = i + step) {
+ uint64_t i64;
+
+ /* extend range for 64-bit */
+ i64 = (uint64_t)i << 32;
+ base = (uint32_t)ceilf(log2(i64));
+ compare = rte_log2_u64(i64);
+ if (base != compare) {
+ printf("Wrong rte_log2_u64(%" PRIx64 ") val %x, expected %x\n",
+ i64, compare, base);
+ return TEST_FAILED;
+ }
+
base = (uint32_t)ceilf(log2((uint32_t)i));
- compare = rte_log2_u32(i);
+ compare = rte_log2_u32((uint32_t)i);
if (base != compare) {
printf("Wrong rte_log2_u32(%x) val %x, expected %x\n",
i, compare, base);
return TEST_FAILED;
}
+ compare = rte_log2_u64((uint64_t)i);
+ if (base != compare) {
+ printf("Wrong rte_log2_u64(%x) val %x, expected %x\n",
+ i, compare, base);
+ return TEST_FAILED;
+ }
}
return 0;
}
--
2.17.1
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