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https://github.com/yuzu-emu/unicorn.git
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e7a7d8c508
This brings down the size of the struct from 56 to 32 bytes on 64-bit,
and to 20 bytes on 32-bit. This leads to memory savings:
Before:
$ find . -name 'tcg.o' | xargs size
text data bss dec hex filename
41131 29800 88 71019 1156b ./aarch64-softmmu/tcg/tcg.o
37969 29416 96 67481 10799 ./x86_64-linux-user/tcg/tcg.o
39354 28816 96 68266 10aaa ./arm-linux-user/tcg/tcg.o
40802 29096 88 69986 11162 ./arm-softmmu/tcg/tcg.o
39417 29672 88 69177 10e39 ./x86_64-softmmu/tcg/tcg.o
After:
$ find . -name 'tcg.o' | xargs size
text data bss dec hex filename
40883 29800 88 70771 11473 ./aarch64-softmmu/tcg/tcg.o
37473 29416 96 66985 105a9 ./x86_64-linux-user/tcg/tcg.o
38858 28816 96 67770 108ba ./arm-linux-user/tcg/tcg.o
40554 29096 88 69738 1106a ./arm-softmmu/tcg/tcg.o
39169 29672 88 68929 10d41 ./x86_64-softmmu/tcg/tcg.o
Note that using an entire byte for some enums that need less than
that wastes a few bits (noticeable in 32 bits, where we use
20 bytes instead of 16) but avoids extraction code, which overall
is a win--I've tested several variations of the patch, and the appended
is the best performer for OpenSSL's bntest by a very small margin:
Before:
$ taskset -c 0 perf stat -r 15 -- x86_64-linux-user/qemu-x86_64 img/bntest-x86_64 >/dev/null
[...]
Performance counter stats for 'x86_64-linux-user/qemu-x86_64 img/bntest-x86_64' (15 runs):
10538.479833 task-clock (msec) # 0.999 CPUs utilized ( +- 0.38% )
772 context-switches # 0.073 K/sec ( +- 2.03% )
0 cpu-migrations # 0.000 K/sec ( +-100.00% )
2,207 page-faults # 0.209 K/sec ( +- 0.08% )
10.552871687 seconds time elapsed ( +- 0.39% )
After:
$ taskset -c 0 perf stat -r 15 -- x86_64-linux-user/qemu-x86_64 img/bntest-x86_64 >/dev/null
Performance counter stats for 'x86_64-linux-user/qemu-x86_64 img/bntest-x86_64' (15 runs):
10459.968847 task-clock (msec) # 0.999 CPUs utilized ( +- 0.30% )
739 context-switches # 0.071 K/sec ( +- 1.71% )
0 cpu-migrations # 0.000 K/sec ( +- 68.14% )
2,204 page-faults # 0.211 K/sec ( +- 0.10% )
10.473900411 seconds time elapsed ( +- 0.30% )
Backports commit 00c8fa9ffeee7458e5ed62c962faf638156c18da from qemu
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| .. | ||
| crypto | ||
| default-configs | ||
| docs | ||
| fpu | ||
| hw | ||
| include | ||
| qapi | ||
| qobject | ||
| qom | ||
| scripts | ||
| target-arm | ||
| target-i386 | ||
| target-m68k | ||
| target-mips | ||
| target-sparc | ||
| tcg | ||
| util | ||
| aarch64.h | ||
| aarch64eb.h | ||
| accel.c | ||
| arm.h | ||
| armeb.h | ||
| CODING_STYLE | ||
| configure | ||
| COPYING | ||
| COPYING.LIB | ||
| cpu-exec-common.c | ||
| cpu-exec.c | ||
| cpus.c | ||
| cputlb.c | ||
| exec.c | ||
| gen_all_header.sh | ||
| glib_compat.c | ||
| HACKING | ||
| header_gen.py | ||
| ioport.c | ||
| LICENSE | ||
| m68k.h | ||
| Makefile | ||
| Makefile.objs | ||
| Makefile.target | ||
| memory.c | ||
| memory_mapping.c | ||
| mips.h | ||
| mips64.h | ||
| mips64el.h | ||
| mipsel.h | ||
| powerpc.h | ||
| qapi-schema.json | ||
| qemu-log.c | ||
| qemu-timer.c | ||
| rules.mak | ||
| softmmu_template.h | ||
| sparc.h | ||
| sparc64.h | ||
| tcg-runtime.c | ||
| translate-all.c | ||
| translate-all.h | ||
| translate-common.c | ||
| unicorn_common.h | ||
| VERSION | ||
| vl.c | ||
| vl.h | ||
| x86_64.h | ||