Changing the waiting_served_ratio default (stack more aggressively by default). (#1820)

# What does this PR do?


This should enable more aggressive by default stacking, meaning better
throughput (in throughput constrained environements).

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Fixes # (issue)


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docs/source/basic_tutorials/launcher.md

@@ -162,7 +162,7 @@ Options:
           This setting is only applied if there is room in the batch as defined by `max_batch_total_tokens`.
           
           [env: WAITING_SERVED_RATIO=]
-          [default: 1.2]
+          [default: 0.3]
 
 ```
 ## MAX_BATCH_PREFILL_TOKENS

launcher/src/main.rs

@@ -251,7 +251,7 @@ struct Args {
     ///
     /// This setting is only applied if there is room in the batch
     /// as defined by `max_batch_total_tokens`.
-    #[clap(default_value = "1.2", long, env)]
+    #[clap(default_value = "0.3", long, env)]
     waiting_served_ratio: f32,
 
     /// Limits the number of tokens for the prefill operation.