milvus/internal/datanode/flow_graph_time_ticker.go
congqixia 0e5931a3da
Add mergedTimetickSender for datanode (#11297)
Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>
2021-11-05 14:59:32 +08:00

113 lines
2.7 KiB
Go

// Licensed to the LF AI & Data foundation under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package datanode
import (
"sync"
"time"
"go.uber.org/atomic"
)
type sendTimeTick func(Timestamp) error
// mergedTimeTickerSender reduces time ticker sending rate when datanode is doing `fast-forwarding`
// it makes sure time ticker send at most 10 times a second (1tick/100millisecond)
// and the last time tick is always sent
type mergedTimeTickerSender struct {
ts atomic.Uint64 // current ts value
cond *sync.Cond // condition to send timeticker
send sendTimeTick // actual sender logic
lastSent time.Time
lastMut sync.RWMutex
wg sync.WaitGroup
closeCh chan struct{}
closeOnce sync.Once
}
func newMergedTimeTickerSender(send sendTimeTick) *mergedTimeTickerSender {
mt := &mergedTimeTickerSender{
cond: sync.NewCond(&sync.Mutex{}),
send: send,
closeCh: make(chan struct{}),
}
mt.ts.Store(0) // 0 for not tt send
mt.wg.Add(2)
go mt.tick()
go mt.work()
return mt
}
func (mt *mergedTimeTickerSender) bufferTs(ts Timestamp) {
mt.ts.Store(ts)
mt.lastMut.RLock()
defer mt.lastMut.RUnlock()
if !mt.lastSent.IsZero() && time.Since(mt.lastSent) > time.Millisecond*100 {
mt.cond.Signal()
}
}
func (mt *mergedTimeTickerSender) tick() {
defer mt.wg.Done()
// this duration might be configuable in the future
t := time.Tick(time.Millisecond * 100) // 100 millisecond, 1/2 of rootcoord timetick duration
for {
select {
case <-t:
mt.cond.Signal() // allow worker to check every 0.1s
case <-mt.closeCh:
return
}
}
}
func (mt *mergedTimeTickerSender) work() {
defer mt.wg.Done()
ts, lastTs := uint64(0), uint64(0)
for {
select {
case <-mt.closeCh:
return
default:
}
mt.cond.L.Lock()
mt.cond.Wait()
ts = mt.ts.Load()
mt.cond.L.Unlock()
if ts != lastTs {
mt.send(ts)
lastTs = ts
mt.lastMut.Lock()
mt.lastSent = time.Now()
mt.lastMut.Unlock()
}
}
}
func (mt *mergedTimeTickerSender) close() {
mt.closeOnce.Do(func() {
close(mt.closeCh)
mt.cond.Broadcast()
mt.wg.Wait()
})
}