Reuse protobuf buffer to decrease memory use. #234
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Gerald Rule: Copy Observability on Veneur and Unilog pull requestscc @stripe/observability |
parser_test.go
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| @@ -414,3 +414,14 @@ func TestServiceCheckMessageUnescape(t *testing.T) { | |||
| assert.NoError(t, err, "Should have parsed correctly") | |||
| assert.Equal(t, "foo\nbar\nbaz\n", svcheck.Message, "Should contain newline") | |||
| } | |||
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| func BenchmarkParseSSF(b *testing.B) { | |||
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Hooray for adding a benchmark function!
samplers/parser.go
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| @@ -43,6 +43,9 @@ type MetricKey struct { | |||
| JoinedTags string `json:"tagstring"` // tags in deterministic order, joined with commas | |||
| } | |||
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| // A reusable protobuf buffer, is not safe to use concurrently! | |||
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nit: it's not exported, but can we stick to godoc style for comments? (That is: // scratchBuff is a reusable protobuf buffer. It is not safe to share between goroutines).
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Yeah, let's definitely add a test for multiple calls to |
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Added! |
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lgtm! |
asf-stripe
reviewed
Aug 25, 2017
samplers/parser.go
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| @@ -84,7 +89,10 @@ func ValidMetric(sample *UDPMetric) bool { | |||
| // It also validates packets before returning them. | |||
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Add a note that this function isn't safe to use concurrently?
This was referenced Aug 28, 2017
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re-approving for rebase |
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Summary
Use a reusable buffer for unmarshaling spans.
Motivation
When inspecting the heap of a box with lots of spans, we noticed a lot of memory usage in decoding protobuf:
I did some digging and found that
proto.Buffercan be reused. I wrote a benchmark that — with-benchmemturned on — yields this:Without buffer reuse:
BenchmarkParseSSF-8 3000000 507 ns/op 384 B/op 3 allocs/opWith buffer reuse:
BenchmarkParseSSF-8 3000000 420 ns/op 176 B/op 2 allocs/opTest plan
Existing tests? Maybe add one that verifies two subsequent calls to
ParseSSFdon't screw anything up?Rollout/monitoring/revert plan
Test out in QA
r? @aditya-stripe