[dpdk-dev] [PATCH] Avoid possible memory cpoy when sort hugepages
Michael Qiu
michael.qiu at intel.com
Wed Dec 10 03:25:41 CET 2014
When the first address is the compared address in the loop,
it will also do memory copy, which is meaningless,
worse more, when hugepg_tbl is mostly in order. This should
be a big deal in large hugepage memory systerm(like hunderd
or thousand GB).
Meanwhile smallest_idx never be a value of -1,so remove this check.
This patch also includes some coding style fix.
Signed-off-by: Michael Qiu <michael.qiu at intel.com>
---
lib/librte_eal/linuxapp/eal/eal_memory.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
index e6cb919..700aba2 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -678,14 +678,13 @@ error:
static int
sort_by_physaddr(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi)
{
- unsigned i, j;
- int compare_idx;
+ unsigned i, j, compare_idx;
uint64_t compare_addr;
struct hugepage_file tmp;
for (i = 0; i < hpi->num_pages[0]; i++) {
compare_addr = 0;
- compare_idx = -1;
+ compare_idx = i;
/*
* browse all entries starting at 'i', and find the
@@ -704,11 +703,9 @@ sort_by_physaddr(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi)
}
}
- /* should not happen */
- if (compare_idx == -1) {
- RTE_LOG(ERR, EAL, "%s(): error in physaddr sorting\n", __func__);
- return -1;
- }
+ /* avoid memory copy when the first entry is the compared */
+ if (compare_idx == i)
+ continue;
/* swap the 2 entries in the table */
memcpy(&tmp, &hugepg_tbl[compare_idx],
--
1.9.3
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