From 41c7e96f1a81ea416ebb3ba45f2815e0202d6b75 Mon Sep 17 00:00:00 2001 From: Bert Belder Date: Sun, 28 Apr 2019 21:31:10 +0200 Subject: Refactor zero-copy buffers for performance and to prevent memory leaks * In order to prevent ArrayBuffers from getting garbage collected by V8, we used to store a v8::Persistent in a map. This patch introduces a custom ArrayBuffer allocator which doesn't use Persistent handles, but instead stores a pointer to the actual ArrayBuffer data alongside with a reference count. Since creating Persistent handles has quite a bit of overhead, this change significantly increases performance. Various HTTP server benchmarks report about 5-10% more requests per second than before. * Previously the Persistent handle that prevented garbage collection had to be released manually, and this wasn't always done, which was causing memory leaks. This has been resolved by introducing a new `PinnedBuf` type in both Rust and C++ that automatically re-enables garbage collection when it goes out of scope. * Zero-copy buffers are now correctly wrapped in an Option if there is a possibility that they're not present. This clears up a correctness issue where we were creating zero-length slices from a null pointer, which is against the rules. --- core/examples/http_bench.rs | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'core/examples') diff --git a/core/examples/http_bench.rs b/core/examples/http_bench.rs index 3e02cdd46..b355f5568 100644 --- a/core/examples/http_bench.rs +++ b/core/examples/http_bench.rs @@ -111,7 +111,10 @@ fn test_record_from() { pub type HttpBenchOp = dyn Future + Send; -fn dispatch(control: &[u8], zero_copy_buf: deno_buf) -> (bool, Box) { +fn dispatch( + control: &[u8], + zero_copy_buf: Option, +) -> (bool, Box) { let record = Record::from(control); let is_sync = record.promise_id == 0; let http_bench_op = match record.op_id { @@ -266,8 +269,9 @@ fn op_close(rid: i32) -> Box { })) } -fn op_read(rid: i32, mut zero_copy_buf: deno_buf) -> Box { +fn op_read(rid: i32, zero_copy_buf: Option) -> Box { debug!("read rid={}", rid); + let mut zero_copy_buf = zero_copy_buf.unwrap(); Box::new( futures::future::poll_fn(move || { let mut table = RESOURCE_TABLE.lock().unwrap(); @@ -285,8 +289,9 @@ fn op_read(rid: i32, mut zero_copy_buf: deno_buf) -> Box { ) } -fn op_write(rid: i32, zero_copy_buf: deno_buf) -> Box { +fn op_write(rid: i32, zero_copy_buf: Option) -> Box { debug!("write rid={}", rid); + let zero_copy_buf = zero_copy_buf.unwrap(); Box::new( futures::future::poll_fn(move || { let mut table = RESOURCE_TABLE.lock().unwrap(); -- cgit v1.2.3