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Specializing cityhash4 on 32-bit architectures can reduce the size of stack frames as well as instruction count. This is a tiny but useful optimization, since some callers invoke it frequently. When specializing into 1/2/3/4-arg versions, the stack usage (in bytes) on some 32-bit arches are listed as follows: - x86: 32, 32, 32, 40 - arm-v7a: 20, 20, 28, 36 - riscv: 0, 0, 0, 16 - power: 16, 16, 16, 32 - mipsel: 8, 8, 8, 24 And each actual argument (even if passing 0) contributes evenly to the number of multiplication instructions generated: - x86: 9, 12, 15 ,18 - arm-v7a: 6, 8, 10, 12 - riscv / power: 12, 18, 20, 24 - mipsel: 9, 12, 15, 19 On 64-bit architectures, the tendencies are similar. But both stack sizes and instruction counts are significantly smaller thus negligible. Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Alexander Motin <mav@FreeBSD.org> Reviewed-by: Tino Reichardt <milky-zfs@mcmilk.de> Signed-off-by: Shengqi Chen <harry-chen@outlook.com> Closes #16131 Closes #16483 |
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| os | ||
| .gitignore | ||
| libzfs_changelist.c | ||
| libzfs_config.c | ||
| libzfs_crypto.c | ||
| libzfs_dataset.c | ||
| libzfs_diff.c | ||
| libzfs_impl.h | ||
| libzfs_import.c | ||
| libzfs_iter.c | ||
| libzfs_mount.c | ||
| libzfs_pool.c | ||
| libzfs_sendrecv.c | ||
| libzfs_status.c | ||
| libzfs_util.c | ||
| libzfs.abi | ||
| libzfs.pc.in | ||
| libzfs.suppr | ||
| Makefile.am | ||
| THIRDPARTYLICENSE.openssl | ||
| THIRDPARTYLICENSE.openssl.descrip | ||