NotificationsYou must be signed in to change notification settings
Fork6
Star31

Commit03a42c9

committed

Use pg_memory_is_all_zeros() in PageIsVerifiedExtended()

Relying on pg_memory_is_all_zeros(), which would apply SIMD instructionswhen dealing with an aligned page, is proving to be at least three timesfaster than the original size_t-based comparisons when checking if aBLCKSZ page is full of zeros. Note that PageIsVerifiedExtended() iscalled each time a page is read from disk, and making it faster is agood thing.Author: Bertrand DrouvotDiscussion:https://postgr.es/m/CAApHDvq7P-JgFhgtxUPqhavG-qSDVUhyWaEX9M8_MNorFEijZA@mail.gmail.com

1 parent5be1dab commit03a42c9Copy full SHA for 03a42c9

File tree

1 file changed

-12

lines changed

src/backend/storage/page
- bufpage.c

1 file changed

-12

lines changed

`‎src/backend/storage/page/bufpage.c`

Lines changed: 1 addition & 12 deletions

Original file line number	Diff line number	Diff line change
`@@ -89,10 +89,8 @@ PageIsVerifiedExtended(Page page, BlockNumber blkno, int flags)`
`89`	`89`	`{`
`90`	`90`	`PageHeaderp= (PageHeader)page;`
`91`	`91`	`size_t*pagebytes;`
`92`		`-inti;`
`93`	`92`	`boolchecksum_failure= false;`
`94`	`93`	`boolheader_sane= false;`
`95`		`-boolall_zeroes= false;`
`96`	`94`	`uint16checksum=0;`
`97`	`95`
`98`	`96`	`/*`
`@@ -126,18 +124,9 @@ PageIsVerifiedExtended(Page page, BlockNumber blkno, int flags)`
`126`	`124`	`}`
`127`	`125`
`128`	`126`	`/* Check all-zeroes case */`
`129`		`-all_zeroes= true;`
`130`	`127`	`pagebytes= (size_t*)page;`
`131`		`-for (i=0;i< (BLCKSZ /sizeof(size_t));i++)`
`132`		`-{`
`133`		`-if (pagebytes[i]!=0)`
`134`		`-{`
`135`		`-all_zeroes= false;`
`136`		`-break;`
`137`		`-}`
`138`		`-}`
`139`	`128`
`140`		`-if (all_zeroes)`
	`129`	`+if (pg_memory_is_all_zeros(pagebytes,BLCKSZ))`
`141`	`130`	`return true;`
`142`	`131`
`143`	`132`	`/*`

0 commit comments

Comments

(0)

Movatterモバイル変換

Navigation Menu

Search code, repositories, users, issues, pull requests...

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Commit03a42c9

File tree

1 file changed

1 file changed

`‎src/backend/storage/page/bufpage.c`

0 commit comments