Commit Graph

8 Commits

Author SHA1 Message Date
beorn7 434a8ed85d Bring back zero-alloc label-value access for metric vecs
Also, fix mutex copy-by-value bug.
2016-08-17 14:01:11 +02:00
beorn7 1f823ab271 Refactor tests
Also, add a "real" collision to the tests.
2016-08-17 12:19:50 +02:00
Stephen J Day 4db77b04a8
metricvec: refactor collision handling to handle equality
After increasing unit test coverage, it was found that the split
function call nature of metric matching wasn't working well in many
cases. By increasing test coverage, we've ensured that both the fast
path and fallback collision path are working appropriately.

With these changes, there is a further performance hit, but now the
results are ensured to be correct.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2016-08-16 18:34:16 -07:00
Stephen J Day 3cf50db5fd
metricvec: handle hash collision for labeled metrics
While hash collisions are quite rare, the current state of the client
library carries a risk of merging two separate label values into a
single metric bucket. The effects are near impossible to detect and the
result will be missing or incorrect counters.

This changeset handles hash collisions by falling back to collision
resolution if multiple label values hash to the same value. This works
similar to separate chaining using a slice. Extra storage is minimized
to only the value key slice to that metrics can be differentiated
within a bucket.

In general, the cost of handling collisions is completely minimized
under normal operation. Performance does show slight increases in
certain areas, but these are more likely statistically anomalies. More
importantly, zero allocation behavior for metrics is preserved on the
fast path. Minimal allocations may be made during collision handling but
this has minimal effect.

Benchmark comparisons with and without collision resolution follow.

```
benchmark                                                         old ns/op     new ns/op     delta
BenchmarkCounterWithLabelValues-4                                 99.0          107           +8.08%
BenchmarkCounterWithLabelValuesConcurrent-4                       79.6          91.0          +14.32%
BenchmarkCounterWithMappedLabels-4                                518           542           +4.63%
BenchmarkCounterWithPreparedMappedLabels-4                        127           137           +7.87%
BenchmarkCounterNoLabels-4                                        19.5          19.1          -2.05%
BenchmarkGaugeWithLabelValues-4                                   97.4          110           +12.94%
BenchmarkGaugeNoLabels-4                                          12.4          10.3          -16.94%
BenchmarkSummaryWithLabelValues-4                                 1204          915           -24.00%
BenchmarkSummaryNoLabels-4                                        936           847           -9.51%
BenchmarkHistogramWithLabelValues-4                               147           147           +0.00%
BenchmarkHistogramNoLabels-4                                      50.6          49.3          -2.57%
BenchmarkHistogramObserve1-4                                      37.9          37.5          -1.06%
BenchmarkHistogramObserve2-4                                      122           137           +12.30%
BenchmarkHistogramObserve4-4                                      310           352           +13.55%
BenchmarkHistogramObserve8-4                                      691           729           +5.50%
BenchmarkHistogramWrite1-4                                        3374          3097          -8.21%
BenchmarkHistogramWrite2-4                                        5310          5051          -4.88%
BenchmarkHistogramWrite4-4                                        12094         10690         -11.61%
BenchmarkHistogramWrite8-4                                        19416         17755         -8.55%
BenchmarkHandler-4                                                11934304      13765894      +15.35%
BenchmarkSummaryObserve1-4                                        1119          1105          -1.25%
BenchmarkSummaryObserve2-4                                        3679          3430          -6.77%
BenchmarkSummaryObserve4-4                                        10678         7982          -25.25%
BenchmarkSummaryObserve8-4                                        22974         16689         -27.36%
BenchmarkSummaryWrite1-4                                          25962         14680         -43.46%
BenchmarkSummaryWrite2-4                                          38019         35073         -7.75%
BenchmarkSummaryWrite4-4                                          78027         56816         -27.18%
BenchmarkSummaryWrite8-4                                          117220        132248        +12.82%
BenchmarkMetricVecWithLabelValuesBasic-4                          138           133           -3.62%
BenchmarkMetricVecWithLabelValues2Keys10ValueCardinality-4        150           144           -4.00%
BenchmarkMetricVecWithLabelValues4Keys10ValueCardinality-4        263           256           -2.66%
BenchmarkMetricVecWithLabelValues2Keys100ValueCardinality-4       145           155           +6.90%
BenchmarkMetricVecWithLabelValues10Keys100ValueCardinality-4      606           634           +4.62%
BenchmarkMetricVecWithLabelValues10Keys1000ValueCardinality-4     746           641           -14.08%

benchmark                                                         old allocs     new allocs     delta
BenchmarkCounterWithLabelValues-4                                 0              0              +0.00%
BenchmarkCounterWithLabelValuesConcurrent-4                       0              0              +0.00%
BenchmarkCounterWithMappedLabels-4                                2              2              +0.00%
BenchmarkCounterWithPreparedMappedLabels-4                        0              0              +0.00%
BenchmarkCounterNoLabels-4                                        0              0              +0.00%
BenchmarkGaugeWithLabelValues-4                                   0              0              +0.00%
BenchmarkGaugeNoLabels-4                                          0              0              +0.00%
BenchmarkSummaryWithLabelValues-4                                 0              0              +0.00%
BenchmarkSummaryNoLabels-4                                        0              0              +0.00%
BenchmarkHistogramWithLabelValues-4                               0              0              +0.00%
BenchmarkHistogramNoLabels-4                                      0              0              +0.00%
BenchmarkMetricVecWithLabelValuesBasic-4                          0              0              +0.00%
BenchmarkMetricVecWithLabelValues2Keys10ValueCardinality-4        0              0              +0.00%
BenchmarkMetricVecWithLabelValues4Keys10ValueCardinality-4        0              0              +0.00%
BenchmarkMetricVecWithLabelValues2Keys100ValueCardinality-4       0              0              +0.00%
BenchmarkMetricVecWithLabelValues10Keys100ValueCardinality-4      0              0              +0.00%
BenchmarkMetricVecWithLabelValues10Keys1000ValueCardinality-4     0              0              +0.00%

benchmark                                                         old bytes     new bytes     delta
BenchmarkCounterWithLabelValues-4                                 0             0             +0.00%
BenchmarkCounterWithLabelValuesConcurrent-4                       0             0             +0.00%
BenchmarkCounterWithMappedLabels-4                                336           336           +0.00%
BenchmarkCounterWithPreparedMappedLabels-4                        0             0             +0.00%
BenchmarkCounterNoLabels-4                                        0             0             +0.00%
BenchmarkGaugeWithLabelValues-4                                   0             0             +0.00%
BenchmarkGaugeNoLabels-4                                          0             0             +0.00%
BenchmarkSummaryWithLabelValues-4                                 0             0             +0.00%
BenchmarkSummaryNoLabels-4                                        0             0             +0.00%
BenchmarkHistogramWithLabelValues-4                               0             0             +0.00%
BenchmarkHistogramNoLabels-4                                      0             0             +0.00%
BenchmarkMetricVecWithLabelValuesBasic-4                          0             0             +0.00%
BenchmarkMetricVecWithLabelValues2Keys10ValueCardinality-4        0             0             +0.00%
BenchmarkMetricVecWithLabelValues4Keys10ValueCardinality-4        0             0             +0.00%
BenchmarkMetricVecWithLabelValues2Keys100ValueCardinality-4       0             0             +0.00%
BenchmarkMetricVecWithLabelValues10Keys100ValueCardinality-4      0             0             +0.00%
BenchmarkMetricVecWithLabelValues10Keys1000ValueCardinality-4     0             0             +0.00%
```

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2016-08-15 16:47:53 -07:00
Stephen J Day c4004ef5f6
benchmark: measure label resolution in MetricVec
Signed-off-by: Stephen J Day <stephen.day@docker.com>
2016-08-15 16:47:42 -07:00
Robert Vollmert 1312da4c0c Inline hash/fnv. 2015-11-09 15:16:26 +01:00
Bjoern Rabenstein d7f8eb1083 Change "Prometheus Team" to "The Prometheus Authors". 2015-02-02 15:14:36 +01:00
Bjoern Rabenstein 5d40912fd2 Complete rewrite of the exposition library.
This rewrite had may backs and forths. In my git repository, it
consists of 35 commits which I cannot group or merge into reasonable
review buckets. Gerrit breaks fundamental git semantics, so I have to
squash the 35 commits into one for the review.

I'll push this not with refs/for/master, but with refs/for/next so
that we can transition after submission in a controlled fashion.

For the review, I recommend to start with looking at godoc and in
particular the many examples. After that, continue with a line-by-line
detailed review. (The big picture is hopefully as expected after
wrapping up the discussion earlier.)

Change-Id: Ib38cc46493a5139ca29d84020650929d94cac850
2014-06-17 14:08:22 +02:00