From 4cec5cb9a2e0c50726b7337fb8221281e155c4cd Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Thu, 18 Feb 2021 14:47:28 +1300 Subject: [PATCH] Specialize checkpointer sort functions. When sorting a potentially large number of dirty buffers, the checkpointer can benefit from a faster sort routine. One reported improvement on a large buffer pool system was 1.4s -> 0.6s. Discussion: https://postgr.es/m/CA%2BhUKGJ2-eaDqAum5bxhpMNhvuJmRDZxB_Tow0n-gse%2BHG0Yig%40mail.gmail.com --- src/backend/storage/buffer/bufmgr.c | 37 +++++++++++++++++------------ 1 file changed, 22 insertions(+), 15 deletions(-) diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 561c212092..7adec2ddc3 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -488,8 +488,8 @@ static void FindAndDropRelFileNodeBuffers(RelFileNode rnode, static void AtProcExit_Buffers(int code, Datum arg); static void CheckForBufferLeaks(void); static int rnode_comparator(const void *p1, const void *p2); -static int buffertag_comparator(const void *p1, const void *p2); -static int ckpt_buforder_comparator(const void *pa, const void *pb); +static inline int buffertag_comparator(const BufferTag *a, const BufferTag *b); +static inline int ckpt_buforder_comparator(const CkptSortItem *a, const CkptSortItem *b); static int ts_ckpt_progress_comparator(Datum a, Datum b, void *arg); @@ -1831,6 +1831,13 @@ UnpinBuffer(BufferDesc *buf, bool fixOwner) } } +#define ST_SORT sort_checkpoint_bufferids +#define ST_ELEMENT_TYPE CkptSortItem +#define ST_COMPARE(a, b) ckpt_buforder_comparator(a, b) +#define ST_SCOPE static +#define ST_DEFINE +#include + /* * BufferSync -- Write out all dirty buffers in the pool. * @@ -1931,8 +1938,7 @@ BufferSync(int flags) * end up writing to the tablespaces one-by-one; possibly overloading the * underlying system. */ - qsort(CkptBufferIds, num_to_scan, sizeof(CkptSortItem), - ckpt_buforder_comparator); + sort_checkpoint_bufferids(CkptBufferIds, num_to_scan); num_spaces = 0; @@ -4595,11 +4601,9 @@ WaitBufHdrUnlocked(BufferDesc *buf) /* * BufferTag comparator. */ -static int -buffertag_comparator(const void *a, const void *b) +static inline int +buffertag_comparator(const BufferTag *ba, const BufferTag *bb) { - const BufferTag *ba = (const BufferTag *) a; - const BufferTag *bb = (const BufferTag *) b; int ret; ret = rnode_comparator(&ba->rnode, &bb->rnode); @@ -4626,12 +4630,9 @@ buffertag_comparator(const void *a, const void *b) * It is important that tablespaces are compared first, the logic balancing * writes between tablespaces relies on it. */ -static int -ckpt_buforder_comparator(const void *pa, const void *pb) +static inline int +ckpt_buforder_comparator(const CkptSortItem *a, const CkptSortItem *b) { - const CkptSortItem *a = (const CkptSortItem *) pa; - const CkptSortItem *b = (const CkptSortItem *) pb; - /* compare tablespace */ if (a->tsId < b->tsId) return -1; @@ -4722,6 +4723,13 @@ ScheduleBufferTagForWriteback(WritebackContext *context, BufferTag *tag) IssuePendingWritebacks(context); } +#define ST_SORT sort_pending_writebacks +#define ST_ELEMENT_TYPE PendingWriteback +#define ST_COMPARE(a, b) buffertag_comparator(&a->tag, &b->tag) +#define ST_SCOPE static +#define ST_DEFINE +#include + /* * Issue all pending writeback requests, previously scheduled with * ScheduleBufferTagForWriteback, to the OS. @@ -4741,8 +4749,7 @@ IssuePendingWritebacks(WritebackContext *context) * Executing the writes in-order can make them a lot faster, and allows to * merge writeback requests to consecutive blocks into larger writebacks. */ - qsort(&context->pending_writebacks, context->nr_pending, - sizeof(PendingWriteback), buffertag_comparator); + sort_pending_writebacks(context->pending_writebacks, context->nr_pending); /* * Coalesce neighbouring writes, but nothing else. For that we iterate -- 2.30.0