From 2bc3c1a41c5b1fb503ce15a144946dc387980fb3 Mon Sep 17 00:00:00 2001
From: HunDunDM <hundundm@gmail.com>
Date: Thu, 8 Jul 2021 16:16:19 +0800
Subject: [PATCH] add tiflash hot write scheduler

Signed-off-by: HunDunDM <hundundm@gmail.com>
---
 server/schedulers/hot_region.go | 44 +++++++++++++++++++++++++--------
 1 file changed, 34 insertions(+), 10 deletions(-)

diff --git a/server/schedulers/hot_region.go b/server/schedulers/hot_region.go
index 62bf9f054625..4d506fce984c 100644
--- a/server/schedulers/hot_region.go
+++ b/server/schedulers/hot_region.go
@@ -558,14 +558,27 @@ func (bs *balanceSolver) solve() []*operator.Operator {
 // its expectation * ratio, the store would be selected as hot source store
 func (bs *balanceSolver) filterSrcStores() map[uint64]*storeLoadDetail {
 	ret := make(map[uint64]*storeLoadDetail)
+	confSrcToleranceRatio := bs.sche.conf.GetSrcToleranceRatio()
+	confEnableForTiFlash := bs.sche.conf.GetEnableForTiFlash()
 	for id, detail := range bs.stLoadDetail {
+		srcToleranceRatio := confSrcToleranceRatio
+		if detail.IsTiFlash {
+			if !confEnableForTiFlash {
+				continue
+			}
+			if bs.rwTy != write || bs.opTy != movePeer {
+				continue
+			}
+			srcToleranceRatio = 0
+		}
 		if len(detail.HotPeers) == 0 {
 			continue
 		}
+
 		minLoad := detail.LoadPred.min()
 		if slice.AllOf(minLoad.Loads, func(i int) bool {
 			if statistics.IsSelectedDim(i) {
-				return minLoad.Loads[i] > bs.sche.conf.GetSrcToleranceRatio()*detail.LoadPred.Expect.Loads[i]
+				return minLoad.Loads[i] > srcToleranceRatio*detail.LoadPred.Expect.Loads[i]
 			}
 			return true
 		}) {
@@ -705,7 +718,7 @@ func (bs *balanceSolver) getRegion() *core.RegionInfo {
 func (bs *balanceSolver) filterDstStores() map[uint64]*storeLoadDetail {
 	var (
 		filters    []filter.Filter
-		candidates []*core.StoreInfo
+		candidates []*storeLoadDetail
 	)
 	srcStore := bs.stLoadDetail[bs.cur.srcStoreID].Store
 	switch bs.opTy {
@@ -718,7 +731,7 @@ func (bs *balanceSolver) filterDstStores() map[uint64]*storeLoadDetail {
 		}
 
 		for _, detail := range bs.stLoadDetail {
-			candidates = append(candidates, detail.Store)
+			candidates = append(candidates, detail)
 		}
 
 	case transferLeader:
@@ -730,9 +743,9 @@ func (bs *balanceSolver) filterDstStores() map[uint64]*storeLoadDetail {
 			filters = append(filters, leaderFilter)
 		}
 
-		for _, store := range bs.cluster.GetFollowerStores(bs.cur.region) {
-			if _, ok := bs.stLoadDetail[store.GetID()]; ok {
-				candidates = append(candidates, store)
+		for _, peer := range bs.cur.region.GetFollowers() {
+			if detail, ok := bs.stLoadDetail[peer.GetStoreId()]; ok {
+				candidates = append(candidates, detail)
 			}
 		}
 
@@ -742,12 +755,23 @@ func (bs *balanceSolver) filterDstStores() map[uint64]*storeLoadDetail {
 	return bs.pickDstStores(filters, candidates)
 }
 
-func (bs *balanceSolver) pickDstStores(filters []filter.Filter, candidates []*core.StoreInfo) map[uint64]*storeLoadDetail {
+func (bs *balanceSolver) pickDstStores(filters []filter.Filter, candidates []*storeLoadDetail) map[uint64]*storeLoadDetail {
 	ret := make(map[uint64]*storeLoadDetail, len(candidates))
-	dstToleranceRatio := bs.sche.conf.GetDstToleranceRatio()
-	for _, store := range candidates {
+	confDstToleranceRatio := bs.sche.conf.GetDstToleranceRatio()
+	confEnableForTiFlash := bs.sche.conf.GetEnableForTiFlash()
+	for _, detail := range candidates {
+		store := detail.Store
+		dstToleranceRatio := confDstToleranceRatio
+		if detail.IsTiFlash {
+			if !confEnableForTiFlash {
+				continue
+			}
+			if bs.rwTy != write || bs.opTy != movePeer {
+				continue
+			}
+			dstToleranceRatio = 0
+		}
 		if filter.Target(bs.cluster.GetOpts(), store, filters) {
-			detail := bs.stLoadDetail[store.GetID()]
 			maxLoads := detail.LoadPred.max().Loads
 			if slice.AllOf(maxLoads, func(i int) bool {
 				if statistics.IsSelectedDim(i) {