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>
In 7d84809fdc 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>
Pierre Le Marre
Ran Benita