diff options
| author | Morten Sørvig <morten.sorvig@qt.io> | 2022-08-26 09:49:52 +0200 |
|---|---|---|
| committer | Morten Sørvig <morten.sorvig@qt.io> | 2022-09-01 15:42:28 +0200 |
| commit | df76a0585f2badb30aa90ccfb52fa9fa33a00784 (patch) | |
| tree | 056592131e94ae15384c1b58f5005f6b167885ef /mkspecs | |
| parent | 50b05e3e2ad969abf4b939d5db2253380e47d775 (diff) | |
wasm: set ALLOW_MEMORY_GROWTH for multi-threaded builds
Unify the settings for single-threaded and multi-threaded builds;
Qt now always enables heap growth by default.
This means we don't have to reserve a large (1GB) fixed memory
size, but can instead set the smaller (50 MB) initial memory size,
like the single-threaded build does.
Enabling threads + memory growth can potentially cause
a performance regression when accessing heap memory from
JavaScript (https://github.com/WebAssembly/design/issues/1271).
We leave it for the application to decide if this applies,
and if the switch to fixed memory should be made.
Change-Id: I96988b072506456685086e55aca4007a146bd70f
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: Mikołaj Boc <Mikolaj.Boc@qt.io>
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>
Diffstat (limited to 'mkspecs')
| -rw-r--r-- | mkspecs/features/wasm/wasm.prf | 19 |
1 files changed, 3 insertions, 16 deletions
diff --git a/mkspecs/features/wasm/wasm.prf b/mkspecs/features/wasm/wasm.prf index 5e6501ed99..5b7dbaf493 100644 --- a/mkspecs/features/wasm/wasm.prf +++ b/mkspecs/features/wasm/wasm.prf @@ -29,29 +29,16 @@ exists($$QMAKE_QT_CONFIG) { message("Setting PTHREAD_POOL_SIZE to" $$POOL_SIZE) EMCC_LFLAGS += -s PTHREAD_POOL_SIZE=$$POOL_SIZE - } else { - EMCC_LFLAGS += -s ALLOW_MEMORY_GROWTH=1 } + # Set memory options + EMCC_LFLAGS += -sALLOW_MEMORY_GROWTH isEmpty(QT_WASM_INITIAL_MEMORY) { - # Hardcode wasm memory size. - - qtConfig(thread) { - # Pthreads and ALLOW_MEMORY_GROWTH can cause javascript wasm memory access to - # be slow. Instead, we specify the memory size - # at build time. Further, browsers limit the maximum initial memory size to 1GB. - # https://github.com/WebAssembly/design/issues/1271 - INITIAL_MEMORY = 1GB - } else { - INITIAL_MEMORY = 50MB # emscripten default is 16MB, we need slightly more - } + INITIAL_MEMORY = 50MB # emscripten default is 16MB, we need slightly more } else { - # QT_WASM_INITIAL_MEMORY must be a multiple of 64KB (i.e. 65536) INITIAL_MEMORY = $$QT_WASM_INITIAL_MEMORY - message("Setting INITIAL_MEMORY to" $$INITIAL_MEMORY) } EMCC_LFLAGS += -s INITIAL_MEMORY=$$INITIAL_MEMORY - message("Setting INITIAL_MEMORY to" $$INITIAL_MEMORY) qtConfig(sse2) { QMAKE_CFLAGS += -O2 -msimd128 -msse -msse2 |