Closed
Bug 1371297
Opened 7 years ago
Closed 7 years ago
stylo: We could shrink ApplicableDeclarationBlock by a word on 64-bit
Categories
(Core :: CSS Parsing and Computation, enhancement)
Tracking
()
RESOLVED
FIXED
People
(Reporter: bzbarsky, Unassigned)
References
(Blocks 1 open bug)
Details
ApplicableDeclarationBlock has 2 words of StyleSource, a u8 for CascadeLevel, a word for usize, and a u32 for specificity. Apparently rust doesn't reorder struct members yet, so we end up with 5 words on both 32-bit and 64-bit. If I move the CascadeLevel to the end, we get 32 bytes on 64-bit instead of 40. Not sure whether it's worth doing this or just waiting for rust to start reordering things.
Comment 1•7 years ago
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(In reply to Boris Zbarsky [:bz] (if a patch has no decent message, automatic r-) from comment #0) > ApplicableDeclarationBlock has 2 words of StyleSource, a u8 for > CascadeLevel, a word for usize, and a u32 for specificity. Apparently rust > doesn't reorder struct members yet, so we end up with 5 words on both 32-bit > and 64-bit. If I move the CascadeLevel to the end, we get 32 bytes on > 64-bit instead of 40. > > Not sure whether it's worth doing this or just waiting for rust to start > reordering things. It is worth doing, IMO. Smaller data structures means more stuff fitting in cache, less memmov, better jemalloc performance, the list goes on.
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Reporter | |
Comment 3•7 years ago
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https://github.com/servo/servo/pull/17242
Flags: needinfo?(bzbarsky)
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Reporter | |
Comment 4•7 years ago
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https://hg.mozilla.org/integration/autoland/rev/16a2f50d486db9d24262b5888a4269ae81d56381
Status: NEW → RESOLVED
Closed: 7 years ago
Resolution: --- → FIXED
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Description
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