feat: a max-performance feature to tune git-repository.

The performance difference is rather drastic at about 2.5x, and
definitely worth having if there is no compatibility issue
due to shared C dependencies in the same binary.

Additionally we setup the makefile to use big object caches
to avoid having to decompress the same object too often, accelerating
the diffing process about 4x, for a total of 10x performance boost.

Author: Byron

Cargo.toml

@@ -14,6 +14,20 @@ include = ["src/**/*", "LICENSE.md", "README.md", "CHANGELOG.md"]
 [lib]
 test = false
 
+[[test]]
+name = "baseline"
+path = "tests/baseline.rs"
+required-features = ["max-performance"]
+
+[[test]]
+name = "baseline-atomic"
+path = "tests/baseline_atomic.rs.rs"
+required-features = ["max-performance"]
+
+[features]
+default = []
+max-performance = ["git-repository/max-performance"]
+
 [dependencies]
 git-repository = { version = "0.28.0", default-features = false, features = ["max-performance-safe", "blocking-network-client", "blocking-http-transport"] }
 serde = { version = "1", features = ["std", "derive"] }

Makefile

@@ -7,9 +7,9 @@ CARGO = $(shell command -v cargo)
 ##@ Development
 
 baseline-atomic: ## run very slow tests that single-step through all commits
-	RUST_BACKTRACE=1 cargo test --test baseline_atomic --release -- --nocapture
+	GITOXIDE_PACK_CACHE_MEMORY=1g GITOXIDE_OBJECT_CACHE_MEMORY=3g RUST_BACKTRACE=1 cargo test --test baseline_atomic --release --features max-performance -- --nocapture
 
 test: ## run all tests with cargo
 	RUST_BACKTRACE=1 cargo test --test crates-index-diff
-	RUST_BACKTRACE=1 cargo test --test baseline --release
+	GITOXIDE_PACK_CACHE_MEMORY=1g RUST_BACKTRACE=1 cargo test --test baseline --release --features max-performance