Merge pull request #13 from uber-go/floor_not_ceil

Use floor(quota) rather than ceil(quota)
uber-go · Feb 23, 2018 · a884895 · a884895
2 parents 6fecebd + 58c8fec
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## v1.2.0 (unreleased)
+
+- Fixed quota clamping to always round down rather than up; Rather than
+  guaranteeing constant throttling at saturation, instead assume that the
+  fractional CPU was added as a hedge for factors outside of Go's scheduler.
+
 ## v1.1.0 (2017-11-10)
 
 - Log the new value of `GOMAXPROCS` rather than the current value.

diff --git a/internal/runtime/cpu_quota_linux.go b/internal/runtime/cpu_quota_linux.go
@@ -41,7 +41,7 @@ func CPUQuotaToGOMAXPROCS(minValue int) (int, CPUQuotaStatus, error) {
 		return -1, CPUQuotaUndefined, err
 	}
 
-	maxProcs := int(math.Ceil(quota))
+	maxProcs := int(math.Floor(quota))
 	if minValue > 0 && maxProcs < minValue {
 		return minValue, CPUQuotaMinUsed, nil
 	}