From: Tom Clegg <tom@curii.com>
Date: Mon, 4 Dec 2023 23:11:47 +0000 (-0500)
Subject: 21227: Don't reduce outgoing request concurrency below 4.
X-Git-Url: https://git.arvados.org/arvados.git/commitdiff_plain/b11dab64f5cd5273247a1ae4c959c25168452a6a

21227: Don't reduce outgoing request concurrency below 4.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@curii.com>
---

diff --git a/sdk/go/arvados/limiter.go b/sdk/go/arvados/limiter.go
index dc944160ab..9edc5386a7 100644
--- a/sdk/go/arvados/limiter.go
+++ b/sdk/go/arvados/limiter.go
@@ -16,6 +16,7 @@ import (
 var (
 	requestLimiterQuietPeriod        = time.Second
 	requestLimiterInitialLimit int64 = 8
+	requestLimiterMinimumLimit int64 = 4
 )
 
 type requestLimiter struct {
@@ -145,6 +146,12 @@ func (rl *requestLimiter) Report(resp *http.Response, err error) bool {
 		if max := rl.current * 2; max < rl.limit {
 			rl.limit = max
 		}
+		if min := requestLimiterMinimumLimit; min > rl.limit {
+			// If limit is too low, programs like
+			// controller and test suites can end up with
+			// too few slots to complete a single request.
+			rl.limit = min
+		}
 		if rl.maxlimit > 0 && rl.maxlimit < rl.limit {
 			rl.limit = rl.maxlimit
 		}