commons: use smallvec to store message arguments

Any message with 4 argument or less will have these arguments stored inline rather than in an heap-allocated vec. The number 4 was chose because almost all messages have 4 arguments or less, and some potentially very spammy messages (wl_touch.move) have exactly 4 arguments. Avoiding allocations in these cases should generally be a gain. Moreother, to avoid bloating the size of Message due to this, String and Array arguments are further boxed, reducing the size of Argument from 4*usize to 2*usize. These kind of arguments are generally pretty rare, so the double allocation should overall not counter the size gain. Closes #268, #249
Smithay · Sep 12, 2019 · b933030 · b933030
1 parent b1d5ec2
commit b933030
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Showing 19 changed files with 106 additions and 68 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -14,6 +14,8 @@
 - [client] the `cursor` and `egl` features are split into their own crates: `wayland-egl` and `wayland-cursor`
 - [server] All dependencies on `calloop` are now removed, `wayland-server` now only exposes a `dispatch(..)`
   and `get_poll_fd()` method, that you are responsible for integrating into your event loop.
+- [commons] Use `smallvec` to store the arguments of messages having 4 or less, drastically reducing the
+  number of allocations when using the rust implementation of the protocol.
 
 ## 0.23.6 -- 2019-09-06
 

diff --git a/tests/protocol_errors.rs b/tests/protocol_errors.rs
@@ -5,6 +5,7 @@ use helpers::{roundtrip, wayc, ways, TestClient, TestServer};
 extern crate nix;
 extern crate wayland_commons as wc;
 
+use wc::smallvec;
 use wc::socket::{BufferedSocket, Socket};
 use wc::wire::{Argument, Message};
 
@@ -28,7 +29,7 @@ fn client_wrong_id() {
         .write_message(&Message {
             sender_id: 1, // wl_display
             opcode: 1,    // wl_registry
-            args: vec![
+            args: smallvec![
                 Argument::NewId(3), // should be 2
             ],
         })
@@ -54,7 +55,7 @@ fn client_wrong_opcode() {
         .write_message(&Message {
             sender_id: 1, // wl_display
             opcode: 42,   // inexistant
-            args: vec![],
+            args: smallvec![],
         })
         .unwrap();
     socket.flush().unwrap();
@@ -78,7 +79,7 @@ fn client_wrong_sender() {
         .write_message(&Message {
             sender_id: 54, // wl_display
             opcode: 0,     // inexistant
-            args: vec![],
+            args: smallvec![],
         })
         .unwrap();
     socket.flush().unwrap();

diff --git a/tests/scanner_assets/client_code.rs b/tests/scanner_assets/client_code.rs
@@ -15,7 +15,7 @@ pub mod wl_foo {
     use super::sys::client::*;
     use super::sys::common::{wl_argument, wl_array, wl_interface, wl_message};
     use super::{
-        types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
+        smallvec, types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
         MessageGroup, Object, ObjectMetadata, Proxy, NULLPTR,
     };
     use std::os::raw::c_char;
@@ -134,18 +134,20 @@ pub mod wl_foo {
                 } => Message {
                     sender_id: sender_id,
                     opcode: 0,
-                    args: vec![
+                    args: smallvec![
                         Argument::Int(number),
                         Argument::Uint(unumber),
-                        Argument::Str(unsafe { ::std::ffi::CString::from_vec_unchecked(text.into()) }),
+                        Argument::Str(Box::new(unsafe {
+                            ::std::ffi::CString::from_vec_unchecked(text.into())
+                        })),
                         Argument::Fixed((float * 256.) as i32),
                         Argument::Fd(file),
                     ],
                 },
                 Request::CreateBar {} => Message {
                     sender_id: sender_id,
                     opcode: 1,
-                    args: vec![Argument::NewId(0)],
+                    args: smallvec![Argument::NewId(0),],
                 },
             }
         }
@@ -369,7 +371,7 @@ pub mod wl_bar {
     use super::sys::client::*;
     use super::sys::common::{wl_argument, wl_array, wl_interface, wl_message};
     use super::{
-        types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
+        smallvec, types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
         MessageGroup, Object, ObjectMetadata, Proxy, NULLPTR,
     };
     use std::os::raw::c_char;
@@ -475,17 +477,17 @@ pub mod wl_bar {
                 } => Message {
                     sender_id: sender_id,
                     opcode: 0,
-                    args: vec![
+                    args: smallvec![
                         Argument::Uint(kind.to_raw()),
                         Argument::Object(target.as_ref().id()),
-                        Argument::Array(metadata),
-                        Argument::Array(metametadata.unwrap_or_else(Vec::new)),
+                        Argument::Array(Box::new(metadata)),
+                        Argument::Array(Box::new(metametadata.unwrap_or_else(Vec::new))),
                     ],
                 },
                 Request::Release => Message {
                     sender_id: sender_id,
                     opcode: 1,
-                    args: vec![],
+                    args: smallvec![],
                 },
                 Request::_Self {
                     _self,
@@ -499,7 +501,7 @@ pub mod wl_bar {
                 } => Message {
                     sender_id: sender_id,
                     opcode: 2,
-                    args: vec![
+                    args: smallvec![
                         Argument::Uint(_self),
                         Argument::Uint(_mut),
                         Argument::Uint(object),
@@ -861,7 +863,7 @@ pub mod wl_display {
     use super::sys::client::*;
     use super::sys::common::{wl_argument, wl_array, wl_interface, wl_message};
     use super::{
-        types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
+        smallvec, types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
         MessageGroup, Object, ObjectMetadata, Proxy, NULLPTR,
     };
     use std::os::raw::c_char;
@@ -1012,7 +1014,7 @@ pub mod wl_registry {
     use super::sys::client::*;
     use super::sys::common::{wl_argument, wl_array, wl_interface, wl_message};
     use super::{
-        types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
+        smallvec, types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
         MessageGroup, Object, ObjectMetadata, Proxy, NULLPTR,
     };
     use std::os::raw::c_char;
@@ -1062,9 +1064,11 @@ pub mod wl_registry {
                 Request::Bind { name, id } => Message {
                     sender_id: sender_id,
                     opcode: 0,
-                    args: vec![
+                    args: smallvec![
                         Argument::Uint(name),
-                        Argument::Str(unsafe { ::std::ffi::CString::from_vec_unchecked(id.0.into()) }),
+                        Argument::Str(Box::new(unsafe {
+                            ::std::ffi::CString::from_vec_unchecked(id.0.into())
+                        })),
                         Argument::Uint(id.1),
                         Argument::NewId(0),
                     ],
@@ -1213,7 +1217,7 @@ pub mod wl_callback {
     use super::sys::client::*;
     use super::sys::common::{wl_argument, wl_array, wl_interface, wl_message};
     use super::{
-        types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
+        smallvec, types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
         MessageGroup, Object, ObjectMetadata, Proxy, NULLPTR,
     };
     use std::os::raw::c_char;

diff --git a/tests/scanner_assets/server_code.rs b/tests/scanner_assets/server_code.rs
@@ -15,7 +15,7 @@ pub mod wl_foo {
     use super::sys::common::{wl_argument, wl_array, wl_interface, wl_message};
     use super::sys::server::*;
     use super::{
-        types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
+        smallvec, types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
         MessageGroup, Object, ObjectMetadata, Resource, NULLPTR,
     };
     use std::os::raw::c_char;
@@ -264,7 +264,7 @@ pub mod wl_foo {
                 Event::Cake { kind, amount } => Message {
                     sender_id: sender_id,
                     opcode: 0,
-                    args: vec![Argument::Uint(kind.to_raw()), Argument::Uint(amount)],
+                    args: smallvec![Argument::Uint(kind.to_raw()), Argument::Uint(amount),],
                 },
             }
         }
@@ -371,7 +371,7 @@ pub mod wl_bar {
     use super::sys::common::{wl_argument, wl_array, wl_interface, wl_message};
     use super::sys::server::*;
     use super::{
-        types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
+        smallvec, types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
         MessageGroup, Object, ObjectMetadata, Resource, NULLPTR,
     };
     use std::os::raw::c_char;
@@ -484,7 +484,7 @@ pub mod wl_bar {
                         },
                         metadata: {
                             if let Some(Argument::Array(val)) = args.next() {
-                                val
+                                *val
                             } else {
                                 return Err(());
                             }
@@ -494,7 +494,7 @@ pub mod wl_bar {
                                 if val.len() == 0 {
                                     None
                                 } else {
-                                    Some(val)
+                                    Some(*val)
                                 }
                             } else {
                                 return Err(());
@@ -692,7 +692,7 @@ pub mod wl_bar {
                 } => Message {
                     sender_id: sender_id,
                     opcode: 0,
-                    args: vec![
+                    args: smallvec![
                         Argument::Uint(_self),
                         Argument::Uint(_mut),
                         Argument::Uint(object),
@@ -850,7 +850,7 @@ pub mod wl_callback {
     use super::sys::common::{wl_argument, wl_array, wl_interface, wl_message};
     use super::sys::server::*;
     use super::{
-        types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
+        smallvec, types_null, AnonymousObject, Argument, ArgumentType, Interface, Main, Message, MessageDesc,
         MessageGroup, Object, ObjectMetadata, Resource, NULLPTR,
     };
     use std::os::raw::c_char;
@@ -951,7 +951,7 @@ pub mod wl_callback {
                 Event::Done { callback_data } => Message {
                     sender_id: sender_id,
                     opcode: 0,
-                    args: vec![Argument::Uint(callback_data)],
+                    args: smallvec![Argument::Uint(callback_data),],
                 },
             }
         }

diff --git a/wayland-client/src/lib.rs b/wayland-client/src/lib.rs
@@ -135,6 +135,7 @@ pub mod protocol {
 
     pub(crate) use crate::{AnonymousObject, Attached, Main, Proxy, ProxyMap};
     pub(crate) use wayland_commons::map::{Object, ObjectMetadata};
+    pub(crate) use wayland_commons::smallvec;
     pub(crate) use wayland_commons::wire::{Argument, ArgumentType, Message, MessageDesc};
     pub(crate) use wayland_commons::{Interface, MessageGroup};
     pub(crate) use wayland_sys as sys;

diff --git a/wayland-client/src/rust_imp/mod.rs b/wayland-client/src/rust_imp/mod.rs
@@ -60,6 +60,7 @@ impl ProxyMap {
 /*
  * Dispatching logic
  */
+#[allow(clippy::large_enum_variant)]
 pub(crate) enum Dispatched {
     Yes,
     NoDispatch(Message, ProxyInner),

diff --git a/wayland-client/src/rust_imp/queues.rs b/wayland-client/src/rust_imp/queues.rs
@@ -264,7 +264,7 @@ fn message_to_rawevent(msg: Message, proxy: &ProxyInner, map: &mut super::ProxyM
         .map(|a| match a {
             Argument::Int(i) => crate::Argument::Int(i),
             Argument::Uint(u) => crate::Argument::Uint(u),
-            Argument::Array(v) => crate::Argument::Array(if v.is_empty() { None } else { Some(v) }),
+            Argument::Array(v) => crate::Argument::Array(if v.is_empty() { None } else { Some(*v) }),
             Argument::Fixed(f) => crate::Argument::Float((f as f32) / 256.),
             Argument::Fd(f) => crate::Argument::Fd(f),
             Argument::Str(cs) => crate::Argument::Str({

diff --git a/wayland-commons/Cargo.toml b/wayland-commons/Cargo.toml
@@ -17,3 +17,4 @@ travis-ci = { repository = "Smithay/wayland-rs" }
 wayland-sys = { version = "0.24.0-pre", path = "../wayland-sys" }
 nix = "0.15"
 spin = "0.5"
+smallvec = "0.6"
diff --git a/wayland-commons/examples/manual_global_list.rs b/wayland-commons/examples/manual_global_list.rs
@@ -5,6 +5,7 @@ use std::os::unix::io::{FromRawFd, IntoRawFd};
 use std::os::unix::net::UnixStream;
 use std::path::PathBuf;
 
+use wc::smallvec;
 use wc::socket::{BufferedSocket, Socket};
 use wc::wire::{Argument, ArgumentType, Message, MessageDesc};
 
@@ -20,7 +21,7 @@ fn main() {
         .write_message(&Message {
             sender_id: 1, // wl_display
             opcode: 1,    // get registry
-            args: vec![
+            args: smallvec![
                 Argument::NewId(2), // id of the created registry
             ],
         })

diff --git a/wayland-commons/src/lib.rs b/wayland-commons/src/lib.rs
@@ -27,6 +27,8 @@ pub mod socket;
 pub mod user_data;
 pub mod wire;
 
+pub use smallvec::smallvec;
+
 /// A group of messages
 ///
 /// This represents a group of message that can be serialized on the protocol wire.

diff --git a/wayland-commons/src/socket.rs b/wayland-commons/src/socket.rs
@@ -435,6 +435,8 @@ mod tests {
 
     use std::ffi::CString;
 
+    use smallvec::smallvec;
+
     fn same_file(a: RawFd, b: RawFd) -> bool {
         let stat1 = ::nix::sys::stat::fstat(a).unwrap();
         let stat2 = ::nix::sys::stat::fstat(b).unwrap();
@@ -463,11 +465,11 @@ mod tests {
         let msg = Message {
             sender_id: 42,
             opcode: 7,
-            args: vec![
+            args: smallvec![
                 Argument::Uint(3),
                 Argument::Fixed(-89),
-                Argument::Str(CString::new(&b"I like trains!"[..]).unwrap()),
-                Argument::Array(vec![1, 2, 3, 4, 5, 6, 7, 8, 9]),
+                Argument::Str(Box::new(CString::new(&b"I like trains!"[..]).unwrap())),
+                Argument::Array(vec![1, 2, 3, 4, 5, 6, 7, 8, 9].into()),
                 Argument::Object(88),
                 Argument::NewId(56),
                 Argument::Int(-25),
@@ -516,7 +518,7 @@ mod tests {
         let msg = Message {
             sender_id: 42,
             opcode: 7,
-            args: vec![
+            args: smallvec![
                 Argument::Fd(1), // stdin
                 Argument::Fd(0), // stdout
             ],
@@ -557,23 +559,23 @@ mod tests {
             Message {
                 sender_id: 42,
                 opcode: 0,
-                args: vec![
+                args: smallvec![
                     Argument::Int(42),
-                    Argument::Str(CString::new(&b"I like trains"[..]).unwrap()),
+                    Argument::Str(Box::new(CString::new(&b"I like trains"[..]).unwrap())),
                 ],
             },
             Message {
                 sender_id: 42,
                 opcode: 1,
-                args: vec![
+                args: smallvec![
                     Argument::Fd(1), // stdin
                     Argument::Fd(0), // stdout
                 ],
             },
             Message {
                 sender_id: 42,
                 opcode: 2,
-                args: vec![
+                args: smallvec![
                     Argument::Uint(3),
                     Argument::Fd(2), // stderr
                 ],
@@ -625,9 +627,9 @@ mod tests {
         let msg = Message {
             sender_id: 2,
             opcode: 0,
-            args: vec![
+            args: smallvec![
                 Argument::Uint(18),
-                Argument::Str(CString::new(&b"wl_shell"[..]).unwrap()),
+                Argument::Str(Box::new(CString::new(&b"wl_shell"[..]).unwrap())),
                 Argument::Uint(1),
             ],
         };