Use pg_memory_is_all_zeros() in PageIsVerifiedExtended()

michaelpq · michaelpq · commit 03a42c9652f8 · 2024-11-18T11:52:35.000+09:00
Relying on pg_memory_is_all_zeros(), which would apply SIMD instructions when dealing with an aligned page, is proving to be at least three times faster than the original size_t-based comparisons when checking if a BLCKSZ page is full of zeros. Note that PageIsVerifiedExtended() is called each time a page is read from disk, and making it faster is a good thing. Author: Bertrand Drouvot Discussion: https://postgr.es/m/CAApHDvq7P-JgFhgtxUPqhavG-qSDVUhyWaEX9M8_MNorFEijZA@mail.gmail.com
diff --git a/src/backend/storage/page/bufpage.c b/src/backend/storage/page/bufpage.c
@@ -89,10 +89,8 @@ PageIsVerifiedExtended(Page page, BlockNumber blkno, int flags)
 {
 	PageHeader	p = (PageHeader) page;
 	size_t	   *pagebytes;
-	int			i;
 	bool		checksum_failure = false;
 	bool		header_sane = false;
-	bool		all_zeroes = false;
 	uint16		checksum = 0;
 
 	/*
@@ -126,18 +124,9 @@ PageIsVerifiedExtended(Page page, BlockNumber blkno, int flags)
 	}
 
 	/* Check all-zeroes case */
-	all_zeroes = true;
 	pagebytes = (size_t *) page;
-	for (i = 0; i < (BLCKSZ / sizeof(size_t)); i++)
-	{
-		if (pagebytes[i] != 0)
-		{
-			all_zeroes = false;
-			break;
-		}
-	}
 
-	if (all_zeroes)
+	if (pg_memory_is_all_zeros(pagebytes, BLCKSZ))
 		return true;
 
 	/*
