/
sessionrequestsplitter.go
163 lines (140 loc) · 4.02 KB
/
sessionrequestsplitter.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
package sessionrequestsplitter
import (
"context"
bssd "github.com/SJTU-OpenNetwork/go-bitswap/sessiondata"
"github.com/ipfs/go-cid"
"github.com/libp2p/go-libp2p-core/peer"
)
const (
minReceivedToAdjustSplit = 2
maxSplit = 16
maxAcceptableDupes = 0.4
minDuplesToTryLessSplits = 0.2
initialSplit = 2
)
type srsMessage interface {
handle(srs *SessionRequestSplitter)
}
// SessionRequestSplitter track how many duplicate and unique blocks come in and
// uses that to determine how much to split up each set of wants among peers.
type SessionRequestSplitter struct {
ctx context.Context
messages chan srsMessage
// data, do not touch outside run loop
receivedCount int
split int
duplicateReceivedCount int
}
// New returns a new SessionRequestSplitter.
func New(ctx context.Context) *SessionRequestSplitter {
srs := &SessionRequestSplitter{
ctx: ctx,
messages: make(chan srsMessage, 10),
split: initialSplit,
}
go srs.run()
return srs
}
// SplitRequest splits a request for the given cids one or more times among the
// given peers.
func (srs *SessionRequestSplitter) SplitRequest(optimizedPeers []bssd.OptimizedPeer, ks []cid.Cid) []bssd.PartialRequest {
resp := make(chan []bssd.PartialRequest, 1)
select {
case srs.messages <- &splitRequestMessage{optimizedPeers, ks, resp}:
case <-srs.ctx.Done():
return nil
}
select {
case splitRequests := <-resp:
return splitRequests
case <-srs.ctx.Done():
return nil
}
}
// RecordDuplicateBlock records the fact that the session received a duplicate
// block and adjusts split factor as neccesary.
func (srs *SessionRequestSplitter) RecordDuplicateBlock() {
select {
case srs.messages <- &recordDuplicateMessage{}:
case <-srs.ctx.Done():
}
}
// RecordUniqueBlock records the fact that the session received a unique block
// and adjusts the split factor as neccesary.
func (srs *SessionRequestSplitter) RecordUniqueBlock() {
select {
case srs.messages <- &recordUniqueMessage{}:
case <-srs.ctx.Done():
}
}
func (srs *SessionRequestSplitter) run() {
for {
select {
case message := <-srs.messages:
message.handle(srs)
case <-srs.ctx.Done():
return
}
}
}
func (srs *SessionRequestSplitter) duplicateRatio() float64 {
return float64(srs.duplicateReceivedCount) / float64(srs.receivedCount)
}
type splitRequestMessage struct {
optimizedPeers []bssd.OptimizedPeer
ks []cid.Cid
resp chan []bssd.PartialRequest
}
func (s *splitRequestMessage) handle(srs *SessionRequestSplitter) {
split := srs.split
// first iteration ignore optimization ratings
peers := make([]peer.ID, len(s.optimizedPeers))
for i, optimizedPeer := range s.optimizedPeers {
peers[i] = optimizedPeer.Peer
}
ks := s.ks
if len(peers) < split {
split = len(peers)
}
peerSplits := splitPeers(peers, split)
if len(ks) < split {
split = len(ks)
}
keySplits := splitKeys(ks, split)
splitRequests := make([]bssd.PartialRequest, 0, len(keySplits))
for i, keySplit := range keySplits {
splitRequests = append(splitRequests, bssd.PartialRequest{Peers: peerSplits[i], Keys: keySplit})
}
s.resp <- splitRequests
}
type recordDuplicateMessage struct{}
func (r *recordDuplicateMessage) handle(srs *SessionRequestSplitter) {
srs.receivedCount++
srs.duplicateReceivedCount++
if (srs.receivedCount > minReceivedToAdjustSplit) && (srs.duplicateRatio() > maxAcceptableDupes) && (srs.split < maxSplit) {
srs.split++
}
}
type recordUniqueMessage struct{}
func (r *recordUniqueMessage) handle(srs *SessionRequestSplitter) {
srs.receivedCount++
if (srs.split > 1) && (srs.duplicateRatio() < minDuplesToTryLessSplits) {
srs.split--
}
}
func splitKeys(ks []cid.Cid, split int) [][]cid.Cid {
splits := make([][]cid.Cid, split)
for i, c := range ks {
pos := i % split
splits[pos] = append(splits[pos], c)
}
return splits
}
func splitPeers(peers []peer.ID, split int) [][]peer.ID {
splits := make([][]peer.ID, split)
for i, p := range peers {
pos := i % split
splits[pos] = append(splits[pos], p)
}
return splits
}