1 files changed, 34 insertions, 7 deletions

diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c
index dbef2314901e..975c6e0434bd 100644
--- a/lib/raid6/algos.c
+++ b/lib/raid6/algos.c
@@ -131,11 +131,12 @@ static inline const struct raid6_recov_calls *raid6_choose_recov(void)
 static inline const struct raid6_calls *raid6_choose_gen(
 	void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks)
 {
-	unsigned long perf, bestperf, j0, j1;
+	unsigned long perf, bestgenperf, bestxorperf, j0, j1;
+	int start = (disks>>1)-1, stop = disks-3;	/* work on the second half of the disks */
 	const struct raid6_calls *const *algo;
 	const struct raid6_calls *best;
 
-	for (bestperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) {
+	for (bestgenperf = 0, bestxorperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) {
 		if (!best || (*algo)->prefer >= best->prefer) {
 			if ((*algo)->valid && !(*algo)->valid())
 				continue;
@@ -153,19 +154,45 @@ static inline const struct raid6_calls *raid6_choose_gen(
 			}
 			preempt_enable();
 
-			if (perf > bestperf) {
-				bestperf = perf;
+			if (perf > bestgenperf) {
+				bestgenperf = perf;
 				best = *algo;
 			}
-			pr_info("raid6: %-8s %5ld MB/s\n", (*algo)->name,
+			pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name,
 			       (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
+
+			if (!(*algo)->xor_syndrome)
+				continue;
+
+			perf = 0;
+
+			preempt_disable();
+			j0 = jiffies;
+			while ((j1 = jiffies) == j0)
+				cpu_relax();
+			while (time_before(jiffies,
+					    j1 + (1<<RAID6_TIME_JIFFIES_LG2))) {
+				(*algo)->xor_syndrome(disks, start, stop,
+						      PAGE_SIZE, *dptrs);
+				perf++;
+			}
+			preempt_enable();
+
+			if (best == *algo)
+				bestxorperf = perf;
+
+			pr_info("raid6: %-8s xor() %5ld MB/s\n", (*algo)->name,
+				(perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1));
 		}
 	}
 
 	if (best) {
-		pr_info("raid6: using algorithm %s (%ld MB/s)\n",
+		pr_info("raid6: using algorithm %s gen() %ld MB/s\n",
 		       best->name,
-		       (bestperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
+		       (bestgenperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
+		if (best->xor_syndrome)
+			pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n",
+			       (bestxorperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1));
 		raid6_call = *best;
 	} else
 		pr_err("raid6: Yikes!  No algorithm found!\n");