diff options
Diffstat (limited to 'vespa-feed-client/src/main/java/ai/vespa/feed/client/impl/DynamicThrottler.java')
-rw-r--r-- | vespa-feed-client/src/main/java/ai/vespa/feed/client/impl/DynamicThrottler.java | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/vespa-feed-client/src/main/java/ai/vespa/feed/client/impl/DynamicThrottler.java b/vespa-feed-client/src/main/java/ai/vespa/feed/client/impl/DynamicThrottler.java index 951a1776b6f..567788b8501 100644 --- a/vespa-feed-client/src/main/java/ai/vespa/feed/client/impl/DynamicThrottler.java +++ b/vespa-feed-client/src/main/java/ai/vespa/feed/client/impl/DynamicThrottler.java @@ -28,12 +28,12 @@ public class DynamicThrottler extends StaticThrottler { public DynamicThrottler(FeedClientBuilderImpl builder) { super(builder); - targetInflight = new AtomicLong(8 * minInflight); + targetInflight = new AtomicLong(minInflight); } @Override public void sent(long __, CompletableFuture<HttpResponse> ___) { - double currentInflight = targetInflight.get(); + double currentInflight = targetInflight(); if (++sent * sent * sent < 1e2 * currentInflight * currentInflight) return; @@ -43,22 +43,36 @@ public class DynamicThrottler extends StaticThrottler { // Use buckets for throughput over inflight, along the log-scale, in [minInflight, maxInflight). int index = (int) (throughputs.length * log(max(1, min(255, currentInflight / minInflight))) - / log(256)); // 4096 (server max streams per connection) / 16 (our min per connection) + / log(256)); // 512 (server max streams per connection) / 2 (our min per connection) throughputs[index] = currentThroughput; // Loop over throughput measurements and pick the one which optimises throughput and latency. - double choice = currentInflight; + double best = currentInflight; double max = -1; - for (int i = throughputs.length; i-- > 0; ) { + int j = -1, k = -1, choice = 0; + double s = 0; + for (int i = 0; i < throughputs.length; i++) { if (throughputs[i] == 0) continue; // Skip unknown values. double inflight = minInflight * pow(256, (i + 0.5) / throughputs.length); double objective = throughputs[i] * pow(inflight, (weight - 1)); // Optimise throughput (weight), but also latency (1 - weight). if (objective > max) { max = objective; - choice = inflight; + best = inflight; + choice = i; } + // Additionally, smooth the throughput values, to reduce the impact of noise, and reduce jumpiness. + if (j != -1) { + double t = throughputs[j]; + if (k != -1) throughputs[j] = (2 * t + throughputs[i] + s) / 4; + s = t; + } + k = j; + j = i; } - long target = (long) ((random() * 0.20 + 0.92) * choice); // Random walk, skewed towards increase. + long target = (long) ((random() * 0.40 + 0.84) * best + random() * 4 - 1); // Random step, skewed towards increase. + // If the best inflight is at the high end of the known, we override the random walk to speed up upwards exploration. + if (choice == j && choice + 1 < throughputs.length) + target = (long) (1 + minInflight * pow(256, (choice + 1.5) / throughputs.length)); targetInflight.set(max(minInflight, min(maxInflight, target))); } |