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l2geth: optimize loops #1027

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merged 4 commits into from
Jun 9, 2021
Merged

l2geth: optimize loops #1027

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5251f10
l2geth: optimize loops
tynes Jun 4, 2021
5b72557
l2geth: stop ticker when done
tynes Jun 7, 2021
b5892ea
l2geth: don't wait for first tick
tynes Jun 7, 2021
f9dee12
chore: add changeset
tynes Jun 9, 2021
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5 changes: 5 additions & 0 deletions .changeset/angry-numbers-swim.md
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Original file line number Diff line number Diff line change
@@ -0,0 +1,5 @@
---
'@eth-optimism/l2geth': patch
---

Optimize main polling loops
13 changes: 7 additions & 6 deletions l2geth/rollup/sync_service.go
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Expand Up @@ -138,17 +138,18 @@ func NewSyncService(ctx context.Context, cfg Config, txpool *core.TxPool, bc *co
}

// Wait until the remote service is done syncing
for {
t := time.NewTicker(10 * time.Second)
for ; true; <-t.C {
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@smartcontracts smartcontracts Jun 8, 2021 •
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Is there a possibility that the ticker goes off while the system is in the middle of syncing? Do we get two threads simultaneously trying to sync? If so, is there a potential problem with both threads trying to sync at the same time?

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Is there a possibility that the ticker goes off while the system is in the middle of syncing?

If the processing that occurs after the tick takes longer than the tick time, then the next tick will be dropped. If the processing takes less time then the code will block on <-t.C until the next tick, see: https://golang.org/src/time/tick.go

	// Give the channel a 1-element time buffer.
	// If the client falls behind while reading, we drop ticks
	// on the floor until the client catches up.

Do we get two threads simultaneously trying to sync? If so, is there a potential problem with both threads trying to sync at the same time?

No, this code is not creating new goroutines and is not used concurrently

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The purpose of the for ; true; <-.t.C syntax over for range t.C is that with the second syntax it will not run the first iteration of the loop until after the first tick. We currently run with a 10 second or so tick which is too long to wait for on boot

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Thanks for the context. LGTM.

status, err := service.client.SyncStatus(service.backend)
if err != nil {
log.Error("Cannot get sync status")
continue
}
if !status.Syncing {
t.Stop()
break
}
log.Info("Still syncing", "index", status.CurrentTransactionIndex, "tip", status.HighestKnownTransactionIndex)
time.Sleep(10 * time.Second)
}

// Initialize the latest L1 data here to make sure that
Expand Down Expand Up @@ -320,7 +321,8 @@ func (s *SyncService) Stop() error {
// VerifierLoop is the main loop for Verifier mode
func (s *SyncService) VerifierLoop() {
log.Info("Starting Verifier Loop", "poll-interval", s.pollInterval, "timestamp-refresh-threshold", s.timestampRefreshThreshold)
for {
t := time.NewTicker(s.pollInterval)
for ; true; <-t.C {
if err := s.updateL1GasPrice(); err != nil {
log.Error("Cannot update L1 gas price", "msg", err)
}
Expand All @@ -330,7 +332,6 @@ func (s *SyncService) VerifierLoop() {
if err := s.updateL2GasPrice(nil); err != nil {
log.Error("Cannot update L2 gas price", "msg", err)
}
time.Sleep(s.pollInterval)
}
}

Expand All @@ -354,7 +355,8 @@ func (s *SyncService) verify() error {
// transactions and then updates the EthContext.
func (s *SyncService) SequencerLoop() {
log.Info("Starting Sequencer Loop", "poll-interval", s.pollInterval, "timestamp-refresh-threshold", s.timestampRefreshThreshold)
for {
t := time.NewTicker(s.pollInterval)
for ; true; <-t.C {
if err := s.updateL1GasPrice(); err != nil {
log.Error("Cannot update L1 gas price", "msg", err)
}
Expand All @@ -370,7 +372,6 @@ func (s *SyncService) SequencerLoop() {
if err := s.updateContext(); err != nil {
log.Error("Could not update execution context", "error", err)
}
time.Sleep(s.pollInterval)
}
}

Expand Down