$ uname -a
Linux c66f2e42d6d7 6.1.51-0-virt #1-Alpine SMP Mon, 04 Sep 2023 08:04:05 +0000 aarch64 GNU/Linux
$ cargo version
cargo 1.72.1 (103a7ff2e 2023-08-15)
$ valgrind --version
valgrind-3.19.0
This is using the code from the master branch, which contains only the
following:
fn main() {
deno_core::JsRuntime::new(deno_core::RuntimeOptions::default());
}I ran DHAT as follows:
$ valgrind --tool=dhat --dhat-out-file=dhat-master.json ./target/debug/rusty-v8-memtest
==20430== DHAT, a dynamic heap analysis tool
==20430== Copyright (C) 2010-2018, and GNU GPL'd, by Mozilla Foundation
==20430== Using Valgrind-3.19.0 and LibVEX; rerun with -h for copyright info
==20430== Command: ./target/debug/rusty-v8-memtest
==20430==
==20430==
==20430== Total: 2,766,579 bytes in 3,128 blocks
==20430== At t-gmax: 664,075 bytes in 1,134 blocks
==20430== At t-end: 36,701 bytes in 659 blocks
==20430== Reads: 11,243,734 bytes
==20430== Writes: 3,642,207 bytes
==20430==
==20430== To view the resulting profile, open
==20430== file:///usr/libexec/valgrind/dh_view.html
==20430== in a web browser, click on "Load...", and then select the file
==20430== /opt/rusty-v8-memtest/dhat-master.json
==20430== The text at the bottom explains the abbreviations used in the output.
See the DHAT viewer results as PDF here.
The code in the jemalloc branch is as follows:
#[cfg(not(target_env = "msvc"))]
use jemallocator::Jemalloc;
#[cfg(not(target_env = "msvc"))]
#[global_allocator]
static GLOBAL: Jemalloc = Jemalloc;
fn main() {
deno_core::JsRuntime::new(deno_core::RuntimeOptions::default());
}The DHAT output is:
$ valgrind --tool=dhat --dhat-out-file=dhat-jemalloc.json ./target/debug/rusty-v8-memtest
==24968== DHAT, a dynamic heap analysis tool
==24968== Copyright (C) 2010-2018, and GNU GPL'd, by Mozilla Foundation
==24968== Using Valgrind-3.19.0 and LibVEX; rerun with -h for copyright info
==24968== Command: ./target/debug/rusty-v8-memtest
==24968==
==24968==
==24968== Total: 2,708,886 bytes in 2,890 blocks
==24968== At t-gmax: 639,278 bytes in 1,034 blocks
==24968== At t-end: 33,909 bytes in 657 blocks
==24968== Reads: 11,190,119 bytes
==24968== Writes: 3,589,676 bytes
==24968==
==24968== To view the resulting profile, open
==24968== file:///usr/libexec/valgrind/dh_view.html
==24968== in a web browser, click on "Load...", and then select the file
==24968== /opt/rusty-v8-memtest/dhat-jemalloc.json
==24968== The text at the bottom explains the abbreviations used in the output.
See the DHAT viewer results here.
Since it looked like some memory was being leaked by the WASM engine, I tried with a custom build of V8 without WASM:
$ GN_ARGS="v8_enable_webassembly=false" V8_FROM_SOURCE=1 cargo build -vvThis gives:
$ valgrind --tool=dhat --dhat-out-file=dhat-no-wasm.json ./target/debug/rusty-v8-memtest
==29611== DHAT, a dynamic heap analysis tool
==29611== Copyright (C) 2010-2018, and GNU GPL'd, by Mozilla Foundation
==29611== Using Valgrind-3.19.0 and LibVEX; rerun with -h for copyright info
==29611== Command: ./target/debug/rusty-v8-memtest
==29611==
Error: unrecognized flag --wasm-test-streaming
The remaining arguments were ignored: --harmony-import-assertions --harmony-import-attributes --no-validate-asm --turbo_fast_api_calls --harmony-change-array-by-copy
Try --help for options
==29611==
==29611== Total: 3,628,306 bytes in 9,378 blocks
==29611== At t-gmax: 853,363 bytes in 1,294 blocks
==29611== At t-end: 18,789 bytes in 553 blocks
==29611== Reads: 34,087,294 bytes
==29611== Writes: 24,618,078 bytes
==29611==
==29611== To view the resulting profile, open
==29611== file:///usr/libexec/valgrind/dh_view.html
==29611== in a web browser, click on "Load...", and then select the file
==29611== /opt/rusty-v8-memtest/dhat-no-wasm.json
==29611== The text at the bottom explains the abbreviations used in the output.
DHAT viewer result here.
Using the custom V8 build above, I tried the same thing with the jemalloc
allocator:
$ valgrind --tool=dhat --dhat-out-file=dhat-jemalloc-no-wasm.json ./target/debug/rusty-v8-memtest
==29649== DHAT, a dynamic heap analysis tool
==29649== Copyright (C) 2010-2018, and GNU GPL'd, by Mozilla Foundation
==29649== Using Valgrind-3.19.0 and LibVEX; rerun with -h for copyright info
==29649== Command: ./target/debug/rusty-v8-memtest
==29649==
Error: unrecognized flag --wasm-test-streaming
The remaining arguments were ignored: --harmony-import-assertions --harmony-import-attributes --no-validate-asm --turbo_fast_api_calls --harmony-change-array-by-copy
Try --help for options
==29649==
==29649== Total: 3,570,441 bytes in 9,129 blocks
==29649== At t-gmax: 825,414 bytes in 1,118 blocks
==29649== At t-end: 15,725 bytes in 549 blocks
==29649== Reads: 33,955,905 bytes
==29649== Writes: 24,576,913 bytes
==29649==
==29649== To view the resulting profile, open
==29649== file:///usr/libexec/valgrind/dh_view.html
==29649== in a web browser, click on "Load...", and then select the file
==29649== /opt/rusty-v8-memtest/dhat-jemalloc-no-wasm.json
==29649== The text at the bottom explains the abbreviations used in the output.
Running dispose and dispose_platform manually seems to help. The following code:
fn main() {
deno_core::JsRuntime::new(deno_core::RuntimeOptions::default());
unsafe {
v8::V8::dispose();
}
v8::V8::dispose_platform();
}Gives:
$ valgrind --tool=dhat --dhat-out-file=dhat-with-dispose.json ./target/debug/rusty-v8-memtest
==3196== DHAT, a dynamic heap analysis tool
==3196== Copyright (C) 2010-2018, and GNU GPL'd, by Mozilla Foundation
==3196== Using Valgrind-3.19.0 and LibVEX; rerun with -h for copyright info
==3196== Command: ./target/debug/rusty-v8-memtest
==3196==
==3196==
==3196== Total: 2,766,643 bytes in 3,129 blocks
==3196== At t-gmax: 664,107 bytes in 1,134 blocks
==3196== At t-end: 6,970 bytes in 47 blocks
==3196== Reads: 11,242,267 bytes
==3196== Writes: 3,645,139 bytes
==3196==
==3196== To view the resulting profile, open
==3196== file:///usr/libexec/valgrind/dh_view.html
==3196== in a web browser, click on "Load...", and then select the file
==3196== /opt/rusty-v8-memtest/dhat-with-dispose.json
==3196== The text at the bottom explains the abbreviations used in the output.