[dpdk-dev] [PATCH] replaced O(n^2) sort in sort_by_physaddr() with qsort() from standard library

[Jay Rolette <rolette@infiniteio.com>]

Signed-off-by: Jay Rolette <rolette@infiniteio.com>
---
 lib/librte_eal/linuxapp/eal/eal_memory.c | 59 +++++++++++---------------------
 1 file changed, 20 insertions(+), 39 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
index bae2507..3656515 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -670,6 +670,25 @@ error:
 	return -1;
 }
 
+static int
+cmp_physaddr(const void *a, const void *b)
+{
+#ifndef RTE_ARCH_PPC_64
+	const struct hugepage_file *p1 = (const struct hugepage_file *)a;
+	const struct hugepage_file *p2 = (const struct hugepage_file *)b;
+#else
+	// PowerPC needs memory sorted in reverse order from x86
+	const struct hugepage_file *p1 = (const struct hugepage_file *)b;
+	const struct hugepage_file *p2 = (const struct hugepage_file *)a;
+#endif
+	if (p1->physaddr < p2->physaddr)
+		return -1;
+	else if (p1->physaddr > p2->physaddr)
+		return 1;
+	else
+		return 0;
+}
+
 /*
  * Sort the hugepg_tbl by physical address (lower addresses first on x86,
  * higher address first on powerpc). We use a slow algorithm, but we won't
@@ -678,45 +697,7 @@ error:
 static int
 sort_by_physaddr(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi)
 {
-	unsigned i, j;
-	int 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;
-
-		/*
-		 * browse all entries starting at 'i', and find the
-		 * entry with the smallest addr
-		 */
-		for (j=i; j< hpi->num_pages[0]; j++) {
-
-			if (compare_addr == 0 ||
-#ifdef RTE_ARCH_PPC_64
-				hugepg_tbl[j].physaddr > compare_addr) {
-#else
-				hugepg_tbl[j].physaddr < compare_addr) {
-#endif
-				compare_addr = hugepg_tbl[j].physaddr;
-				compare_idx = j;
-			}
-		}
-
-		/* should not happen */
-		if (compare_idx == -1) {
-			RTE_LOG(ERR, EAL, "%s(): error in physaddr sorting\n", __func__);
-			return -1;
-		}
-
-		/* swap the 2 entries in the table */
-		memcpy(&tmp, &hugepg_tbl[compare_idx],
-			sizeof(struct hugepage_file));
-		memcpy(&hugepg_tbl[compare_idx], &hugepg_tbl[i],
-			sizeof(struct hugepage_file));
-		memcpy(&hugepg_tbl[i], &tmp, sizeof(struct hugepage_file));
-	}
+	qsort(hugepg_tbl, hpi->num_pages[0], sizeof(struct hugepage_file), cmp_physaddr);
 	return 0;
 }
 
-- 
1.9.3 (Apple Git-50)