unicorn/qemu/target
Emilio G. Cota 9aaad9ed27
target/arm: optimize indirect branches
Speed up indirect branches by jumping to the target if it is valid.

Softmmu measurements (see later commit for user-mode results):

Note: baseline (i.e. speedup == 1x) is QEMU v2.9.0.

- Impact on Boot time

| setup | ARM debian jessie boot+shutdown time | stddev |
|--------+--------------------------------------+--------|
| v2.9.0 | 8.84 | 0.07 |
| +cross | 8.85 | 0.03 |
| +jr | 8.83 | 0.06 |

- NBench, arm-softmmu (debian jessie guest). Host: Intel i7-4790K @ 4.00GHz

1.3x +-+-------------------------------------------------------------------------------------------------------------+-+
| |
| cross #### |
1.25x +cross+jr..........................................................#++#.........................................+-+
| #### # # |
| +++# # # # |
| +++ **** # # # |
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/eOLmZNR

NB. 'cross' represents the previous commit.

Backports commit 8a6b28c7b5104263344508df0f4bce97f22cfcaf from qemu
2018-03-02 21:18:15 -05:00
..
arm target/arm: optimize indirect branches 2018-03-02 21:18:15 -05:00
i386 i386: Don't override -cpu options on -cpu host/max 2018-03-02 14:22:45 -05:00
m68k Move target-* CPU file into a target/ folder 2018-03-01 22:50:58 -05:00
mips target/mips: fix delay slot detection in gen_msa_branch() 2018-03-02 14:15:50 -05:00
sparc cputlb and arm/sparc targets: convert mmuidx flushes from varg to bitmap 2018-03-02 10:12:40 -05:00