@@ -22,6 +22,8 @@
#include "exec/tb-hash-xx.h"
+#ifdef CONFIG_SOFTMMU
+
/* Only the bottom TB_JMP_PAGE_BITS of the jump cache hash bits vary for
addresses on the same page. The top bits are the same. This allows
TLB invalidation to quickly clear a subset of the hash table. */
@@ -45,6 +47,16 @@ static inline unsigned int tb_jmp_cache_hash_func(target_ulong pc)
| (tmp & TB_JMP_ADDR_MASK));
}
+#else
+
+/* In user-mode we can get better hashing because we do not have a TLB */
+static inline unsigned int tb_jmp_cache_hash_func(target_ulong pc)
+{
+ return (pc ^ (pc >> TB_JMP_CACHE_BITS)) & (TB_JMP_CACHE_SIZE - 1);
+}
+
+#endif /* CONFIG_SOFTMMU */
+
static inline
uint32_t tb_hash_func(tb_page_addr_t phys_pc, target_ulong pc, uint32_t flags)
{
Optimizations to cross-page chaining and indirect branches make performance more sensitive to the hit rate of tb_jmp_cache. The constraint of reserving some bits for the page number lowers the achievable quality of the hashing function. However, user-mode does not have this requirement. Thus, with this change we use for user-mode a hashing function that is both faster and of better quality than the previous one. Measurements: Note: baseline (i.e. speedup == 1x) is QEMU v2.9.0. - SPECint06 (test set), x86_64-linux-user. Host: Intel i7-6700K @ 4.00GHz 2x +-+--------------------------------------------------------------------------------------------------------------+-+ | +++++ | | jr+noinline | | | | jr+inline ++%%@ | 1.8x +-+jr+hash+noinline +..............................................|%%@...................................+-+ |jr+multhash+inline |%%@+ | | jr+hash+inline +$$$%@ | | ++##|$%@ +++ | 1.6x +-+....................................................................|##|$%@....................+%%%...........+-+ | @@+ **#+$%@ $$+% | | $$$%@+ +**#+$%@ ++++ ++$$+%@ | | ++++ $ $%@ **# $%@ +$$%@@+++$$ %@ | 1.4x +-+.....................+%%%@..........##+$%@..........................**#.$%@...........+$$%.@***$$.%@..........+-+ | ++$$+%@ ##+$%@ **# $%@ $$% @* *#$+%@ | | ***#$ %@ +**# $%@ **# $%@ +###$% @* *#$ %@ | | *+*#$ %@ +%%@+**# $%@ **# $%@ **+#$% @*+*#$ %@ +%%%@+ | 1.2x +-+..................*.*#$.%@***#$$%@+**#.$%@..........................**#.$%@.........**.#$%.@*.*#$.%@***#$+%@+.+-+ | +++ * *#$ %@* *# $%@ **# $%@ +++++++ **# $%@ +++%%@@** #$% @* *#$ %@*+*#$ %@ | | ++###$%+ * *#$ %@* *# $%@ **# $%@ **##$%@@ **# $%@+**#$$%+@** #$% @* *#$ %@* *#$ %@ | | +**+#$%@@ ++$$@@@* *#$ %@* *# $%@ **# $%@ ** #$% @+###++@@++++%%%+ **# $%@ **# $% @** #$% @* *#$ %@* *#$ %@ | 1x +-++-**+#$%-@**##$%+@*+*#$+%@*+*#+$%@+**#+$%@+**+#$%+@**+#$+@@***#$+%@+**#+$%@+**#+$%+@**+#$%+@*+*#$+%@*-*#$+%@-++-+ | ** #$% @** #$% @* *#$ %@* *# $%@ **# $%@ ** #$% @** #$%%@* *#$ %@ **# $%@ **# $% @** #$% @* *#$ %@* *#$ %@ | | ** #$% @** #$% @* *#$ %@* *# $%@ **# $%@ ** #$% @** #$+%@* *#$ %@ **# $%@ **# $% @** #$% @* *#$ %@* *#$ %@ | | ** #$% @** #$% @* *#$ %@* *# $%@ **# $%@ ** #$% @** #$ %@* *#$ %@ **# $%@ **# $% @** #$% @* *#$ %@* *#$ %@ | 0.8x +-+--**##$%@@**##$%@@***#$%%@***#$$%@-**#$$%@-**##$%@@**##$%%@***#$%%@-**#$$%@-**#$$%@@**##$%@@***#$%%@***#$%%@--+-+ astar bzip2 gcc gobmk h264ref hmmlibquantum mcf omnetpperlbench sjengxalancbmk hmean png: http://imgur.com/1ZJGjzV Here I also tried the hash function suggested by Paolo ("multhash"): return ((uint64_t) (pc * 2654435761) >> 32) & (); As you can see it is just as good as the other new function ("hash"), but I kept "hash" because with it all benchmarks have speedup > 1. - SPECint06 (train set), x86_64-linux-user. Host: Intel i7-6700K @ 4.00GHz 2.6x +-+--------------------------------------------------------------------------------------------------------------+-+ | | | jr+inline | 2.4x +jr+inline+hash....................................................................................###...........+-+ | # # | | # # | 2.2x +-+................................................................................................#.#...........+-+ | # # | | # # | 2x +-+................................................................................................#.#...........+-+ | # # | | **** # | 1.8x +-+.............................................................................................*..*.#...........+-+ | +++ #### * * # | | #### ****++# * * # | 1.6x +-+......................................+++...........................****..#.*++*..#..........*..*.#...........+-+ | #### *++* # * * # +++ * * # | | +++ ++#++# * * # * * # #### * * # | 1.4x +-+...................+++###..........****..#..........................*..*..#.*..*..#....#..#..*..*.#...........+-+ | ****+# * * # * * # * * # *** # * * # #### | | *++* # +++ * * # * * # * * # *+* # * * # ****++# | 1.2x +-+...................*..*.#..****###.*..*..#..........................*..*..#.*..*..#..*.*..#..*..*.#..*..*..#..+-+ | ****### +++ * * # * * # * * # * * # * * # * * # * * # * * # | | * *++# ***### * * # * * # * * # * * # * * # * * # * * # * * # | 1x +-+--****###--***###--****##--****###-****###--***###--***###--****##--****###-****###--***###--****##--****###--+-+ astar bzip2 gcc gobmk h264ref hmmlibquantum mcf omnetpperlbench sjengxalancbmk hmean png: http://imgur.com/1D2VFze - NBench, x86_64-linux-user. Host: Intel i7-6700K @ 4.00GHz 1.1x +-+-------------------------------------------------------------------------------------------------------------+-+ | | | jr+inline | 1.08x +jr+hash+noinline +..............................+++.....................................................+-+ | jr+hash+inline | | | +++| | | | |+++ | 1.06x +-+....................................................|.|.|....................................................+-+ | |###| +++++ | | |#|#| ###$$$ | 1.04x +-+.........................+++....+++.+++.............|#|#$$$..............................++#|#++$............+-+ | |+++ |+++| ****|#| $ +++ |#+# $ | | | | | | | * |*+#| $ |+++ **** # $ | | +++ +++ | | ****| | * |* #++$ | |+++ * |* # $ | 1.02x +-+....|..................|####$$.*.|*|$$$$.++++++++.*.|*.#..$..........****|.|............*++*.#..$.++++++++...+-+ | ***+++ |# |#|$ * |*##| $ | | | * |* # $ * |*| | +++ * * # $ ***###$$ | | *|* |+++ +++ +++ *** |#|$ * |*|#| $ ***###$$ *++* # $ +++ * |*##$$$ ####++ * * # $ *+*++# $ | 1x +-++-+*+*###+++****-$$$$+*+*++#+$+*++*+#++$+*+*++#+$+*++*-#++$+++-++$$$+*++*+#++$+***++#$$+*++*-#++$+*+*++#+$+-++-+ | * *++#$$ *++*|$++$ *|*++# $ * *+#++$ *+*++#|$ * * # $ *** |$+$ * *|#| $ *+* #+$ * * # $ * * # $ | | * * #+$ * *## $ *+* # $ * * # $ * * #+$ * * # $ *+*### $ * *|#++$ * * # $ * * # $ * * # $ | | * * # $ * *|# $ * * # $ * * # $ * * # $ * * # $ * *++# $ * *+# $ * * # $ * * # $ * * # $ | 0.98x +-+...*.*..#.$.*..*+#..$.*.*..#.$.*..*.#..$.*.*..#.$.*..*.#..$.*.*..#.$.*..*.#..$.*.*..#.$.*..*.#..$.*.*..#.$...+-+ | * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ | | * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ * * # $ | 0.96x +-+---***###$$-****##$$$-***###$$-****##$$$-***###$$-****##$$$-***###$$-****##$$$-***###$$-****##$$$-***###$$---+-+ ASSIGNMENT BITFIELD FOURFP EMULATION HUFFMAN LU DECOMPOSITIONEURAL NNUMERIC SOSTRING SORT hmean png: http://imgur.com/xK9YfOB - NBench, arm-linux-user. Host: Intel i7-4790K @ 4.00GHz 1.3x +-+-------------------------------------------------------------------------------------------------------------+-+ | #### +++ | | jr+inline #++# #### | 1.25x +jr+hash+inline..............#..#...........................................#++#................................+-+ | # # # # | | # # # # | | # # # # | 1.2x +-+..........................#..#..................................####.....#..#................................+-+ | # # +++#++# # # | | # # ***** # # # | 1.15x +-+..........................#..#..............................*+++*..#.....#..#................................+-+ | # # * * # **** # | | # # * * # *++* # | | # # * * # * * # | 1.1x +-+..........................#..#...............+++............*...*..#..*..*..#................................+-+ | # # +++#### * * # * * # #### | | # # ***** # * * # * * # # # | 1.05x +-+..........................#..#...........*...*..#...........*...*..#..*..*..#...............####......#..#...+-+ | # # +++ * * # * * # * * # #++# ***** # | | +++# # ****### * * # ****### * * # * * # +++# # * * # | | ++++++ ****### ***** # *++*++# * * # *++*++# * * # * * # ++++++ **** # * * # | 1x +-++-+*****###++*++*++#++*+-+*++#+-*++*++#-+*+++*-+#++*++*++#++*+-+*++#+-*++*++#-+*****###++*++*++#++*+-+*++#+-++-+ | *+++*++# * * # * * # * * # * * # * * # * * # * * # * * # * * # * * # | | * * # * * # * * # * * # * * # * * # * * # * * # * * # * * # * * # | 0.95x +-+---*****###--****###--*****###--****###--*****###--****###--*****###--****###--*****###--****###--*****###---+-+ ASSIGNMENT BITFIELD FOURFP EMULATION HUFFMAN LU DECOMPOSITIONEURAL NNUMERIC SOSTRING SORT hmean png: http://imgur.com/uhIEOA1 Signed-off-by: Emilio G. Cota <cota@braap.org> --- include/exec/tb-hash.h | 12 ++++++++++++ 1 file changed, 12 insertions(+)