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Merge pull request #1447 from weaveworks/1441-cache-size

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Remove cache from SmartMerger.
This commit is contained in:
Paul Bellamy
2016-05-09 10:51:23 +01:00
parent c749bb9f20 2dae03501e
commit 2d10a6a9a6
2 changed files with 10 additions and 40 deletions
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28
app/merger.go
View File

@@ -38,13 +38,11 @@ type smartMerger struct {
cache gcache.Cache
}
// NewSmartMerger makes a Merger which merges together reports, caching intermediate merges
// to accelerate future merges. Idea is to cache pair-wise merged reports, forming a merge
// tree. Merging a new report into this tree should be log(N).
// NewSmartMerger makes a Merger which merges together reports as
// a binary tree of reports. Speed up comes from the fact that
// most merges are between small reports.
func NewSmartMerger() Merger {
return &smartMerger{
cache: gcache.New(1000).LRU().Build(),
}
return smartMerger{}
}
type node struct {
@@ -66,11 +64,7 @@ func hash(ids ...string) uint64 {
return id.Sum64()
}
func (s *smartMerger) ClearCache() {
s.cache.Purge()
}
func (s *smartMerger) Merge(reports []report.Report) report.Report {
func (s smartMerger) Merge(reports []report.Report) report.Report {
// Start with a sorted list of leaves.
// Note we must dedupe reports with the same ID to ensure the
// algorithm below doesn't go into an infinite loop. This is
@@ -93,18 +87,10 @@ func (s *smartMerger) Merge(reports []report.Report) report.Report {
// Define how to merge two nodes together. The result of merging
// two reports is cached.
merge := func(left, right *node) *node {
id := hash(left.rpt.ID, right.rpt.ID)
if result, err := s.cache.Get(id); err == nil {
return result.(*node)
}
n := &node{
id: id,
return &node{
id: hash(left.rpt.ID, right.rpt.ID),
rpt: report.MakeReport().Merge(left.rpt).Merge(right.rpt),
}
s.cache.Set(id, n)
return n
}
// Define how to reduce n nodes to 1.

22
app/merger_test.go
View File

@@ -69,20 +69,16 @@ func TestSmartMerger(t *testing.T) {
}
func BenchmarkSmartMerger(b *testing.B) {
benchmarkMerger(b, app.NewSmartMerger(), false)
}
func BenchmarkSmartMergerWithoutCaching(b *testing.B) {
benchmarkMerger(b, app.NewSmartMerger(), true)
benchmarkMerger(b, app.NewSmartMerger())
}
func BenchmarkDumbMerger(b *testing.B) {
benchmarkMerger(b, app.MakeDumbMerger(), false)
benchmarkMerger(b, app.MakeDumbMerger())
}
const numHosts = 15
func benchmarkMerger(b *testing.B, merger app.Merger, clearCache bool) {
func benchmarkMerger(b *testing.B, merger app.Merger) {
makeReport := func() report.Report {
rpt := report.MakeReport()
for i := 0; i < 100; i++ {
@@ -95,12 +91,6 @@ func benchmarkMerger(b *testing.B, merger app.Merger, clearCache bool) {
for i := 0; i < numHosts*5; i++ {
reports = append(reports, makeReport())
}
merger.Merge(reports) // prime the cache
if clearable, ok := merger.(interface {
ClearCache()
}); ok && clearCache {
clearable.ClearCache()
}
b.ReportAllocs()
b.ResetTimer()
@@ -112,11 +102,5 @@ func benchmarkMerger(b *testing.B, merger app.Merger, clearCache bool) {
}
merger.Merge(reports)
if clearable, ok := merger.(interface {
ClearCache()
}); ok && clearCache {
clearable.ClearCache()
}
}
}