28 lines
1.3 KiB
YAML
28 lines
1.3 KiB
YAML
define: DUK_USE_LITCACHE_SIZE
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introduced: 2.3.0
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default: 256
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tags:
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- performance
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- lowmemory
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description: >
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Size of the literal cache, which maps C literal memory addresses into
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pinned duk_hstring heap object addresses. The cache is used when
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application code calls one of the duk_xxx_literal() API call variants,
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such as duk_push_literal() or duk_get_prop_literal(), to speed up the
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string intern check for the literal. In successful cases this caching
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makes using duk_xxx_literal() almost as fast as using borrowed heap
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pointers with duk_xxx_heapptr().
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When this option is defined, duk_hstrings related to literals encountered
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in duk_xxx_literal() API calls are automatically pinned between
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mark-and-sweep rounds. This accomplishes two things. First, it avoids the
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need for cache invalidation for the literal cache in normal operation between
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mark-and-sweep rounds. Second, it reduces string table traffic (i.e. freeing
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and reallocating) for literals which are likely to occur again and again.
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However, the downside is that some strings that may occur only temporarily
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will remain pinned until the next mark-and-sweep round. If this matter, you
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can avoid it by simply using e.g. duk_xxx_string() when dealing with such
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strings.
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The literal cache size must be a power of two (2^N).
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