Make repository evmap-only

Author: jonhoo

Cargo.toml

@@ -1,2 +1,36 @@
-[workspace]
-members = ["evmap", "left-right"]
+[package]
+name = "evmap"
+version = "11.0.0-alpha.6"
+authors = ["Jon Gjengset <[email protected]>"]
+edition = "2018"
+license = "MIT OR Apache-2.0"
+
+description = "A lock-free, eventually consistent, concurrent multi-value map."
+repository = "https://github.com/jonhoo/rust-evmap.git"
+
+keywords = ["map","multi-value","lock-free"]
+categories = ["concurrency", "data-structures"]
+
+[badges]
+azure-devops = { project = "jonhoo/jonhoo", pipeline = "evmap", build = "8" }
+codecov = { repository = "jonhoo/rust-evmap", branch = "master", service = "github" }
+maintenance = { status = "passively-maintained" }
+
+[features]
+default = []
+indexed = ["indexmap"]
+eviction = ["indexed", "rand"]
+amortize = ["indexmap-amortized", "hashbag/amortize"]
+
+[dependencies]
+indexmap = { version = "1.6.1", optional = true }
+indexmap-amortized = { version = "1.6.1", optional = true }
+smallvec = "1.0.0"
+hashbag = "0.1.3"
+rand = { version = "0.7", default-features = false, features = ["alloc"], optional = true }
+left-right = { version = "0.11.0" }
+
+[dev-dependencies]
+quickcheck = "0.9"
+quickcheck_macros = "0.9"
+rand = "0.7"

README.md

@@ -1,28 +1,36 @@
-This crate holds the implementation of the `left-right` concurrency
-primitive, and its primary user `evmap`. See the documentation for each
-crate for details.
-
-Left-right is a concurrency primitive for high concurrency reads over a
-single-writer data structure. The primitive keeps two copies of the
-backing data structure, one that is accessed by readers, and one that is
-access by the (single) writer. This enables all reads to proceed in
-parallel with minimal coordination, and shifts the coordination overhead
-to the writer. In the absence of writes, reads scale linearly with the
-number of cores.
-
-[![Build Status](https://dev.azure.com/jonhoo/jonhoo/_apis/build/status/evmap?branchName=master)](https://dev.azure.com/jonhoo/jonhoo/_build/latest?definitionId=8&branchName=master)
-[![Codecov](https://codecov.io/github/jonhoo/rust-evmap/coverage.svg?branch=master)](https://codecov.io/gh/jonhoo/rust-evmap)
-
-**left-right**
-
-[![Crates.io](https://img.shields.io/crates/v/left-right.svg)](https://crates.io/crates/left-right)
-[![Documentation](https://docs.rs/left-right/badge.svg)](https://docs.rs/left-right/)
-
-**evmap**
-
 [![Crates.io](https://img.shields.io/crates/v/evmap.svg)](https://crates.io/crates/evmap)
 [![Documentation](https://docs.rs/evmap/badge.svg)](https://docs.rs/evmap/)
 
+A lock-free, eventually consistent, concurrent multi-value map.
+
+This map implementation allows reads and writes to execute entirely in parallel, with no
+implicit synchronization overhead. Reads never take locks on their critical path, and neither
+do writes assuming there is a single writer (multi-writer is possible using a `Mutex`), which
+significantly improves performance under contention. It is backed by the
+concurrency primitive [`left-right`](https://crates.io/crates/left-right).
+
+The trade-off exposed by this module is one of eventual consistency: writes are not visible to
+readers except following explicit synchronization. Specifically, readers only see the
+operations that preceeded the last call to `WriteHandle::flush` by a writer. This lets
+writers decide how stale they are willing to let reads get. They can refresh the map after
+every write to emulate a regular concurrent `HashMap`, or they can refresh only occasionally to
+reduce the synchronization overhead at the cost of stale reads.
+
+For read-heavy workloads, the scheme used by this module is particularly useful. Writers can
+afford to refresh after every write, which provides up-to-date reads, and readers remain fast
+as they do not need to ever take locks.
+
+The map is multi-value, meaning that every key maps to a *collection* of values. This
+introduces some memory cost by adding a layer of indirection through a `Vec` for each value,
+but enables more advanced use. This choice was made as it would not be possible to emulate such
+functionality on top of the semantics of this map (think about it -- what would the operational
+log contain?).
+
+To facilitate more advanced use-cases, each of the two maps also carry some customizeable
+meta-information. The writers may update this at will, and when a refresh happens, the current
+meta will also be made visible to readers. This could be useful, for example, to indicate what
+time the refresh happened.
+
 ## Performance
 
 **These benchmarks are outdated at this point, but communicate the right

azure-pipelines.yml

@@ -1,81 +1,68 @@
-stages:
- - stage: left_right
-   jobs:
-    - template: default.yml@templates
-      parameters:
-        minrust: 1.40.0
-        dir: "left-right"
- - stage: evmap
-   jobs:
-    - template: default.yml@templates
-      parameters:
-        minrust: 1.48.0
-        codecov_token: $(CODECOV_TOKEN_SECRET)
-        dir: "evmap"
-    - job: benchmark
-      displayName: "Check that benchmark compiles"
-      pool:
-        vmImage: ubuntu-latest
-      steps:
-        - template: install-rust.yml@templates
-        - script: cargo check
-          displayName: cargo check benchmark/
-          workingDirectory: "evmap/benchmark"
-    - job: miri
-      displayName: "Run miri on test suite"
-      pool:
-        vmImage: ubuntu-latest
-      steps:
-        - bash: |
-            echo '##vso[task.setvariable variable=nightly]nightly-'$(curl -s https://rust-lang.github.io/rustup-components-history/x86_64-unknown-linux-gnu/miri)
-          displayName: "Determine latest miri nightly"
-        - template: install-rust.yml@templates
-          parameters:
-            rust: $(nightly)
-            components:
-              - miri
-        - script: cargo miri setup
-          displayName: cargo miri setup
-          workingDirectory: "evmap"
-        - script: cargo miri test
-          displayName: cargo miri test
-          workingDirectory: "evmap"
-          env:
-            QUICKCHECK_TESTS: 500
-    - job: asan
-      displayName: "Run address sanitizer on test suite"
-      pool:
-        vmImage: ubuntu-latest
-      steps:
-        - template: install-rust.yml@templates
-          parameters:
-            rust: nightly
-        - bash: |
-              sudo ln -s /usr/bin/llvm-symbolizer-6.0 /usr/bin/llvm-symbolizer
-          displayName: Enable debug symbols
-        # only --lib --tests b/c of https://github.com/rust-lang/rust/issues/53945
-        - script: |
-              env ASAN_OPTIONS="detect_odr_violation=0" RUSTFLAGS="-Z sanitizer=address" cargo test --lib --tests --target x86_64-unknown-linux-gnu
-          displayName: cargo -Z sanitizer=address test
-          workingDirectory: "evmap"
-    - job: lsan
-      displayName: "Run leak sanitizer on test suite"
-      pool:
-        vmImage: ubuntu-latest
-      steps:
-        - template: install-rust.yml@templates
-          parameters:
-            rust: nightly
-        - bash: |
-              sudo ln -s /usr/bin/llvm-symbolizer-6.0 /usr/bin/llvm-symbolizer
-              sed -i '/\[features\]/i [profile.dev]' Cargo.toml
-              sed -i '/profile.dev/a opt-level = 1' Cargo.toml
-              cat Cargo.toml
-          displayName: Enable debug symbols
-        - script: |
-              env RUSTFLAGS="-Z sanitizer=leak" cargo test --target x86_64-unknown-linux-gnu
-          displayName: cargo -Z sanitizer=leak test
-          workingDirectory: "evmap"
+jobs:
+ - template: default.yml@templates
+   parameters:
+     minrust: 1.48.0
+     codecov_token: $(CODECOV_TOKEN_SECRET)
+ - job: benchmark
+   displayName: "Check that benchmark compiles"
+   pool:
+     vmImage: ubuntu-latest
+   steps:
+     - template: install-rust.yml@templates
+     - script: cargo check
+       displayName: cargo check benchmark/
+       workingDirectory: "benchmark"
+ - job: miri
+   displayName: "Run miri on test suite"
+   pool:
+     vmImage: ubuntu-latest
+   steps:
+     - bash: |
+         echo '##vso[task.setvariable variable=nightly]nightly-'$(curl -s https://rust-lang.github.io/rustup-components-history/x86_64-unknown-linux-gnu/miri)
+       displayName: "Determine latest miri nightly"
+     - template: install-rust.yml@templates
+       parameters:
+         rust: $(nightly)
+         components:
+           - miri
+     - script: cargo miri setup
+       displayName: cargo miri setup
+     - script: cargo miri test
+       displayName: cargo miri test
+       env:
+         QUICKCHECK_TESTS: 500
+ - job: asan
+   displayName: "Run address sanitizer on test suite"
+   pool:
+     vmImage: ubuntu-latest
+   steps:
+     - template: install-rust.yml@templates
+       parameters:
+         rust: nightly
+     - bash: |
+           sudo ln -s /usr/bin/llvm-symbolizer-6.0 /usr/bin/llvm-symbolizer
+       displayName: Enable debug symbols
+     # only --lib --tests b/c of https://github.com/rust-lang/rust/issues/53945
+     - script: |
+           env ASAN_OPTIONS="detect_odr_violation=0" RUSTFLAGS="-Z sanitizer=address" cargo test --lib --tests --target x86_64-unknown-linux-gnu
+       displayName: cargo -Z sanitizer=address test
+ - job: lsan
+   displayName: "Run leak sanitizer on test suite"
+   pool:
+     vmImage: ubuntu-latest
+   steps:
+     - template: install-rust.yml@templates
+       parameters:
+         rust: nightly
+     - bash: |
+           sudo ln -s /usr/bin/llvm-symbolizer-6.0 /usr/bin/llvm-symbolizer
+           sed -i '/\[features\]/i [profile.dev]' Cargo.toml
+           sed -i '/profile.dev/a opt-level = 1' Cargo.toml
+           cat Cargo.toml
+       displayName: Enable debug symbols
+     - script: |
+           env RUSTFLAGS="-Z sanitizer=leak" cargo test --target x86_64-unknown-linux-gnu
+       displayName: cargo -Z sanitizer=leak test
 
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