Prefer cooperative compression over offload to blocking pool.

actix-http/CHANGES.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Revise compression middleware to perform compression cooperatively, periodically yielding control to other tasks instead of offloading compression to a background thread.
+
 ## 3.4.0
 
 ### Added

actix-http/Cargo.toml

@@ -140,3 +140,8 @@ required-features = ["http2", "rustls-0_21"]
 name = "response-body-compression"
 harness = false
 required-features = ["compress-brotli", "compress-gzip", "compress-zstd"]
+
+[[bench]]
+name = "compression-chunk-size"
+harness = false
+required-features = ["compress-brotli", "compress-gzip", "compress-zstd"]

actix-http/benches/compression-chunk-size.rs

@@ -0,0 +1,51 @@
+#![allow(clippy::uninlined_format_args)]
+
+use actix_http::{body, encoding::Encoder, ContentEncoding, ResponseHead, StatusCode};
+use criterion::{criterion_group, criterion_main, Criterion};
+
+const BODY: &[u8] = include_bytes!("../../Cargo.lock");
+
+const CHUNK_SIZES: [usize; 7] = [512, 1024, 2048, 4096, 8192, 16384, 32768];
+
+const CONTENT_ENCODING: [ContentEncoding; 4] = [
+    ContentEncoding::Deflate,
+    ContentEncoding::Gzip,
+    ContentEncoding::Zstd,
+    ContentEncoding::Brotli,
+];
+
+fn compression_responses(c: &mut Criterion) {
+    static_assertions::const_assert!(BODY.len() > CHUNK_SIZES[6]);
+
+    let mut group = c.benchmark_group("time to compress chunk");
+
+    for content_encoding in CONTENT_ENCODING {
+        for chunk_size in CHUNK_SIZES {
+            group.bench_function(
+                format!("{}-{}", content_encoding.as_str(), chunk_size),
+                |b| {
+                    let rt = actix_rt::Runtime::new().unwrap();
+                    b.iter(|| {
+                        rt.block_on(async move {
+                            let encoder = Encoder::response(
+                                content_encoding,
+                                &mut ResponseHead::new(StatusCode::OK),
+                                &BODY[..chunk_size],
+                            )
+                            .with_encode_chunk_size(chunk_size);
+                            body::to_bytes_limited(encoder, chunk_size + 256)
+                                .await
+                                .unwrap()
+                                .unwrap();
+                        });
+                    });
+                },
+            );
+        }
+    }
+
+    group.finish();
+}
+
+criterion_group!(benches, compression_responses);
+criterion_main!(benches);