mirror of
https://github.com/Motorhead1991/qemu.git
synced 2025-08-04 00:03:54 -06:00
ef1ac71ff0
Before, via pahole:
arm32, a 32-bit host which aligns uint64_t:
struct Property {
const char * name; /* 0 4 */
const PropertyInfo * info; /* 4 4 */
ptrdiff_t offset; /* 8 4 */
uint8_t bitnr; /* 12 1 */
/* XXX 3 bytes hole, try to pack */
uint64_t bitmask; /* 16 8 */
_Bool set_default; /* 24 1 */
/* XXX 7 bytes hole, try to pack */
union {
int64_t i; /* 32 8 */
uint64_t u; /* 32 8 */
} defval; /* 32 8 */
int arrayoffset; /* 40 4 */
const PropertyInfo * arrayinfo; /* 44 4 */
int arrayfieldsize; /* 48 4 */
const char * link_type; /* 52 4 */
/* size: 56, cachelines: 1, members: 11 */
/* sum members: 46, holes: 2, sum holes: 10 */
};
arm64, an arbitrary 64-bit host:
struct Property {
const char * name; /* 0 8 */
const PropertyInfo * info; /* 8 8 */
ptrdiff_t offset; /* 16 8 */
uint8_t bitnr; /* 24 1 */
/* XXX 7 bytes hole, try to pack */
uint64_t bitmask; /* 32 8 */
_Bool set_default; /* 40 1 */
/* XXX 7 bytes hole, try to pack */
union {
int64_t i; /* 48 8 */
uint64_t u; /* 48 8 */
} defval; /* 48 8 */
int arrayoffset; /* 56 4 */
/* XXX 4 bytes hole, try to pack */
const PropertyInfo * arrayinfo; /* 64 8 */
int arrayfieldsize; /* 72 4 */
/* XXX 4 bytes hole, try to pack */
const char * link_type; /* 80 8 */
/* size: 88, cachelines: 2, members: 11 */
/* sum members: 66, holes: 4, sum holes: 22 */
};
Afterward there are no holes in either structure.
For arm32, size 48, padding 2, saved 8 bytes.
For arm64, size 72, padding 6, saved 16 bytes.
Saves 20k from qemu-system-aarch64 on a 64-bit host.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Lei Yang <leiyang@redhat.com>
Link: https://lore.kernel.org/r/20241218134251.4724-22-richard.henderson@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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|---|---|---|
| .. | ||
| authz | ||
| block | ||
| chardev | ||
| crypto | ||
| disas | ||
| exec | ||
| fpu | ||
| gdbstub | ||
| hw | ||
| io | ||
| libdecnumber | ||
| migration | ||
| monitor | ||
| net | ||
| qapi | ||
| qemu | ||
| qom | ||
| scsi | ||
| semihosting | ||
| standard-headers | ||
| sysemu | ||
| tcg | ||
| ui | ||
| user | ||
| elf.h | ||
| glib-compat.h | ||
| qemu-io.h | ||
| qemu-main.h | ||