scripts/perfect_hash.py


Log

Author Commit Date CI Message
Ran Benita 5d297c50 2021-04-08T10:13:27 scripts: update license note in perfect_hash.py Ref: https://github.com/ilanschnell/perfect-hash/issues/5 Signed-off-by: Ran Benita <ran@unusedvar.com>
Ran Benita 45b1ca22 2021-04-01T22:46:56 keysym: speed up the perfect hash function Make it use a bit operation instead of an expensive modulo. perf diff: Baseline Delta Abs Shared Object Symbol ........ ......... ................. ................................... 28.15% -6.57% bench-compose [.] xkb_keysym_from_name Signed-off-by: Ran Benita <ran@unusedvar.com>
Ran Benita 68e69b7d 2021-03-28T20:22:54 keysym: use a perfect hash function for case sensitive xkb_keysym_from_name In 7d84809fdccbb5898d0838849ec7c321410182d5 I added a fast path for the case-sensitive case, but it is still slowing down Compose parsing. Instead of the binary search, use a perfect hash function, computed with a simple python module I found (vendored). It is faster -- perf diff is: Baseline Delta Abs Shared Object Symbol ........ ......... ................. ................................... 22.35% -14.04% libc-2.33.so [.] __strcmp_avx2 16.75% +10.28% bench-compose [.] xkb_keysym_from_name 20.72% +2.40% bench-compose [.] parse.constprop.0 2.29% -1.97% bench-compose [.] strcmp@plt 2.56% +1.81% bench-compose [.] resolve_name 2.37% +0.92% libc-2.33.so [.] __GI_____strtoull_l_internal 26.19% -0.63% bench-compose [.] lex 1.45% +0.56% libc-2.33.so [.] __memchr_avx2 1.13% -0.31% libc-2.33.so [.] __strcpy_avx2 Also reduces the binary size: Before: text data bss dec hex filename 341111 5064 8 346183 54847 build/libxkbcommon.so.0.0.0 After: text data bss dec hex filename 330215 5064 8 335287 51db7 build/libxkbcommon.so.0.0.0 Note however that it's still larger than before 7d84809fdccbb5898d08388: text data bss dec hex filename 320617 5168 8 325793 4f8a1 build/libxkbcommon.so.0.0.0 Signed-off-by: Ran Benita <ran@unusedvar.com>