JS_GetGCParameter

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Syntax
Description
See Also

Adjust performance parameters related to garbage collection.

Syntax

uint32_t
JS_GetGCParameter(JSRuntime *rt, JSGCParamKey key);

void
JS_SetGCParameter(JSRuntime *rt, JSGCParamKey key, uint32_t value);

uint32_t
JS_GetGCParameterForThread(JSContext *cx, JSGCParamKey key); // Added in SpiderMonkeySidebar 17

void
JS_SetGCParameterForThread(JSContext *cx, JSGCParamKey key, uint32_t value); // Added in SpiderMonkeySidebar 17

Name	Type	Description
`rt`	`JSRuntime *`	The runtime to configure.
`cx`	`JSContext *`	The context to configure. Requires request. In a `JS_THREADSAFE` build, the caller must be in a request on this `JSContext`.
`key`	`JSGCParamKey`	Specifies which garbage collection parameter to get or set.
`value`	`uint32_t`	(`JS_SetGCParameter` only) The value to assign to the parameter.

typedef enum JSGCParamKey {
    JSGC_MAX_BYTES,
    JSGC_MAX_MALLOC_BYTES,
    JSGC_BYTES,
    JSGC_NUMBER,
    JSGC_MAX_CODE_CACHE_BYTES,
    JSGC_MODE,
    JSGC_UNUSED_CHUNKS,
    JSGC_TOTAL_CHUNKS,
    JSGC_SLICE_TIME_BUDGET,
    JSGC_MARK_STACK_LIMIT,
    JSGC_HIGH_FREQUENCY_TIME_LIMIT,
    JSGC_HIGH_FREQUENCY_LOW_LIMIT,
    JSGC_HIGH_FREQUENCY_HIGH_LIMIT,
    JSGC_HIGH_FREQUENCY_HEAP_GROWTH_MAX,
    JSGC_HIGH_FREQUENCY_HEAP_GROWTH_MIN,
    JSGC_LOW_FREQUENCY_HEAP_GROWTH,
    JSGC_DYNAMIC_HEAP_GROWTH,
    JSGC_DYNAMIC_MARK_SLICE,
    JSGC_ALLOCATION_THRESHOLD,
    JSGC_DECOMMIT_THRESHOLD,
    JSGC_MIN_EMPTY_CHUNK_COUNT,
    JSGC_MAX_EMPTY_CHUNK_COUNT,
} JSGCParamKey;

Value	Description
`JSGC_MAX_BYTES`	Maximum nominal heap before last ditch GC.
`JSGC_MAX_MALLOC_BYTES`	Number of JS_malloc bytes before last ditch GC.
`JSGC_BYTES`	Amount of bytes allocated by the GC. Added in SpiderMonkey 1.8.1
`JSGC_NUMBER`	Number of times GC has been invoked. Includes both major and minor GC. Added in SpiderMonkey 1.8.1
`JSGC_MAX_CODE_CACHE_BYTES`	Max size of the code cache in bytes. Added in SpiderMonkey 17
`JSGC_MODE`	Select GC mode. Added in SpiderMonkey 17
`JSGC_UNUSED_CHUNKS`	Number of cached empty GC chunks Added in SpiderMonkey 17.
`JSGC_TOTAL_CHUNKS`	Total number of allocated GC chunks. Added in SpiderMonkey 17
`JSGC_SLICE_TIME_BUDGET`	Max milliseconds to spend in an incremental GC slice. Added in SpiderMonkey 17
`JSGC_MARK_STACK_LIMIT`	Maximum size the GC mark stack can grow to. Added in SpiderMonkey 17
`JSGC_HIGH_FREQUENCY_TIME_LIMIT`	GCs less than this far apart in time will be considered 'high-frequency GCs'. See setGCLastBytes in jsgc.cpp. Added in SpiderMonkey 17
`JSGC_HIGH_FREQUENCY_LOW_LIMIT`	Start of dynamic heap growth. Added in SpiderMonkey 17
`JSGC_HIGH_FREQUENCY_HIGH_LIMIT`	End of dynamic heap growth. Added in SpiderMonkey 17
`JSGC_HIGH_FREQUENCY_HEAP_GROWTH_MAX`	Upper bound of heap growth. Added in SpiderMonkey 17
`JSGC_HIGH_FREQUENCY_HEAP_GROWTH_MIN`	Lower bound of heap growth. Added in SpiderMonkey 17
`JSGC_LOW_FREQUENCY_HEAP_GROWTH`	Heap growth for low frequency GCs. Added in SpiderMonkey 17
`JSGC_DYNAMIC_HEAP_GROWTH`	If false, the heap growth factor is fixed at 3. If true, it is determined based on whether GCs are high- or low- frequency. Added in SpiderMonkey 17
`JSGC_DYNAMIC_MARK_SLICE`	If true, high-frequency GCs will use a longer mark slice. Added in SpiderMonkey 17
`JSGC_ALLOCATION_THRESHOLD`	Lower limit after which we limit the heap growth. Added in SpiderMonkey 24
`JSGC_DECOMMIT_THRESHOLD`	We decommit memory lazily. If more than this number of megabytes is available to be decommitted, then JS_MaybeGC will trigger a shrinking GC to decommit it. Added in SpiderMonkey 24
`JSGC_MIN_EMPTY_CHUNK_COUNT`	We try to keep at least this many unused chunks in the free chunk pool at all times, even after a shrinking GC. Added in SpiderMonkey 38
`JSGC_MAX_EMPTY_CHUNK_COUNT`	We never keep more than this many unused chunks in the free chunk pool.Added in SpiderMonkey 38

Description

JS_GetGCParameter returns the current parameter of the garbage collection.

If successful, JS_GetGCParameter returns the current parameter.

JS_SetGCParameter ajusts the parameter of the garbage collection.

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Contributors to this page: arai, fscholz, tschneidereit, Jorend, Sheppy

Last updated by: arai, Dec 25, 2014, 5:50:29 AM

JS_GetGCParameter

Syntax

Description

See Also

Document Tags and Contributors