Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fanout: reduce allocation related to staleness tracking #2405

Merged
merged 1 commit into from
Jan 15, 2025
Merged

Fanout: reduce allocation related to staleness tracking #2405

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions CHANGELOG.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,10 @@ internal API changes are not present.
Main (unreleased)
-----------------

### Enhancements

- Improved performance by reducing allocation in Prometheus write pipelines by ~30% (@thampiotr)

v1.6.0-rc.1
-----------------

Expand Down
39 changes: 20 additions & 19 deletions internal/component/prometheus/fanout.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@ import (
"github.com/prometheus/prometheus/model/metadata"
"github.com/prometheus/prometheus/scrape"
"github.com/prometheus/prometheus/storage"
"go.uber.org/atomic"

"github.com/grafana/alloy/internal/service/labelstore"
)
Expand All @@ -29,6 +30,10 @@ type Fanout struct {
writeLatency prometheus.Histogram
samplesCounter prometheus.Counter
ls labelstore.LabelStore

// lastSeriesCount stores the number of series that were sent through the last appender. It helps to estimate how
// much memory to allocate for the staleness trackers.
lastSeriesCount atomic.Int64
}

// NewFanout creates a fanout appendable.
Expand Down Expand Up @@ -77,11 +82,8 @@ func (f *Fanout) Appender(ctx context.Context) storage.Appender {

app := &appender{
children: make([]storage.Appender, 0),
componentID: f.componentID,
writeLatency: f.writeLatency,
samplesCounter: f.samplesCounter,
ls: f.ls,
stalenessTrackers: make([]labelstore.StalenessTracker, 0),
fanout: f,
stalenessTrackers: make([]labelstore.StalenessTracker, 0, f.lastSeriesCount.Load()),
}

for _, x := range f.children {
Expand All @@ -95,12 +97,9 @@ func (f *Fanout) Appender(ctx context.Context) storage.Appender {

type appender struct {
children []storage.Appender
componentID string
writeLatency prometheus.Histogram
samplesCounter prometheus.Counter
start time.Time
ls labelstore.LabelStore
stalenessTrackers []labelstore.StalenessTracker
fanout *Fanout
}

var _ storage.Appender = (*appender)(nil)
Expand All @@ -111,7 +110,7 @@ func (a *appender) Append(ref storage.SeriesRef, l labels.Labels, t int64, v flo
a.start = time.Now()
}
if ref == 0 {
ref = storage.SeriesRef(a.ls.GetOrAddGlobalRefID(l))
ref = storage.SeriesRef(a.fanout.ls.GetOrAddGlobalRefID(l))
}
a.stalenessTrackers = append(a.stalenessTrackers, labelstore.StalenessTracker{
GlobalRefID: uint64(ref),
Expand All @@ -129,7 +128,7 @@ func (a *appender) Append(ref storage.SeriesRef, l labels.Labels, t int64, v flo
}
}
if updated {
a.samplesCounter.Inc()
a.fanout.samplesCounter.Inc()
}
return ref, multiErr
}
Expand All @@ -138,7 +137,8 @@ func (a *appender) Append(ref storage.SeriesRef, l labels.Labels, t int64, v flo
func (a *appender) Commit() error {
defer a.recordLatency()
var multiErr error
a.ls.TrackStaleness(a.stalenessTrackers)
a.fanout.lastSeriesCount.Store(int64(len(a.stalenessTrackers)))
a.fanout.ls.TrackStaleness(a.stalenessTrackers)
for _, x := range a.children {
err := x.Commit()
if err != nil {
Expand All @@ -151,7 +151,8 @@ func (a *appender) Commit() error {
// Rollback satisfies the Appender interface.
func (a *appender) Rollback() error {
defer a.recordLatency()
a.ls.TrackStaleness(a.stalenessTrackers)
a.fanout.lastSeriesCount.Store(int64(len(a.stalenessTrackers)))
a.fanout.ls.TrackStaleness(a.stalenessTrackers)
var multiErr error
for _, x := range a.children {
err := x.Rollback()
Expand All @@ -167,7 +168,7 @@ func (a *appender) recordLatency() {
return
}
duration := time.Since(a.start)
a.writeLatency.Observe(duration.Seconds())
a.fanout.writeLatency.Observe(duration.Seconds())
}

// AppendExemplar satisfies the Appender interface.
Expand All @@ -176,7 +177,7 @@ func (a *appender) AppendExemplar(ref storage.SeriesRef, l labels.Labels, e exem
a.start = time.Now()
}
if ref == 0 {
ref = storage.SeriesRef(a.ls.GetOrAddGlobalRefID(l))
ref = storage.SeriesRef(a.fanout.ls.GetOrAddGlobalRefID(l))
}
var multiErr error
for _, x := range a.children {
Expand All @@ -194,7 +195,7 @@ func (a *appender) UpdateMetadata(ref storage.SeriesRef, l labels.Labels, m meta
a.start = time.Now()
}
if ref == 0 {
ref = storage.SeriesRef(a.ls.GetOrAddGlobalRefID(l))
ref = storage.SeriesRef(a.fanout.ls.GetOrAddGlobalRefID(l))
}
var multiErr error
for _, x := range a.children {
Expand All @@ -211,7 +212,7 @@ func (a *appender) AppendHistogram(ref storage.SeriesRef, l labels.Labels, t int
a.start = time.Now()
}
if ref == 0 {
ref = storage.SeriesRef(a.ls.GetOrAddGlobalRefID(l))
ref = storage.SeriesRef(a.fanout.ls.GetOrAddGlobalRefID(l))
}
var multiErr error
for _, x := range a.children {
Expand All @@ -228,7 +229,7 @@ func (a *appender) AppendCTZeroSample(ref storage.SeriesRef, l labels.Labels, t,
a.start = time.Now()
}
if ref == 0 {
ref = storage.SeriesRef(a.ls.GetOrAddGlobalRefID(l))
ref = storage.SeriesRef(a.fanout.ls.GetOrAddGlobalRefID(l))
}
var multiErr error
for _, x := range a.children {
Expand All @@ -244,7 +245,7 @@ func (a *appender) AppendCTZeroSample(ref storage.SeriesRef, l labels.Labels, t,
type NoopMetadataStore map[string]scrape.MetricMetadata

// GetMetadata implements the MetricMetadataStore interface.
func (ms NoopMetadataStore) GetMetadata(familyName string) (scrape.MetricMetadata, bool) {
func (ms NoopMetadataStore) GetMetadata(_ string) (scrape.MetricMetadata, bool) {
return scrape.MetricMetadata{}, false
}

Expand Down
9 changes: 8 additions & 1 deletion internal/component/prometheus/interceptor.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@ import (
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/model/metadata"
"github.com/prometheus/prometheus/storage"
"go.uber.org/atomic"

"github.com/grafana/alloy/internal/service/labelstore"
)
Expand All @@ -26,6 +27,10 @@ type Interceptor struct {
next storage.Appendable

ls labelstore.LabelStore

// lastSeriesCount stores the number of series that were sent through the last interceptappender. It helps to estimate how
// much memory to allocate for the staleness trackers.
lastSeriesCount atomic.Int64
}

var _ storage.Appendable = (*Interceptor)(nil)
Expand Down Expand Up @@ -91,7 +96,7 @@ func (f *Interceptor) Appender(ctx context.Context) storage.Appender {
app := &interceptappender{
interceptor: f,
ls: f.ls,
stalenessTrackers: make([]labelstore.StalenessTracker, 0),
stalenessTrackers: make([]labelstore.StalenessTracker, 0, f.lastSeriesCount.Load()),
}
if f.next != nil {
app.child = f.next.Appender(ctx)
Expand Down Expand Up @@ -130,6 +135,7 @@ func (a *interceptappender) Append(ref storage.SeriesRef, l labels.Labels, t int

// Commit satisfies the Appender interface.
func (a *interceptappender) Commit() error {
a.interceptor.lastSeriesCount.Store(int64(len(a.stalenessTrackers)))
a.ls.TrackStaleness(a.stalenessTrackers)
if a.child == nil {
return nil
Expand All @@ -139,6 +145,7 @@ func (a *interceptappender) Commit() error {

// Rollback satisfies the Appender interface.
func (a *interceptappender) Rollback() error {
a.interceptor.lastSeriesCount.Store(int64(len(a.stalenessTrackers)))
a.ls.TrackStaleness(a.stalenessTrackers)
if a.child == nil {
return nil
Expand Down
Loading