Mercurial > hg > nginx
view src/core/ngx_crc.h @ 9167:3038bd4d7816
Core: changed ngx_queue_sort() to use merge sort.
This improves nginx startup times significantly when using very large number
of locations due to computational complexity of the sorting algorithm being
used: insertion sort is O(n*n) on average, while merge sort is O(n*log(n)).
In particular, in a test configuration with 20k locations total startup
time is reduced from 8 seconds to 0.9 seconds.
Prodded by Yusuke Nojima,
https://mailman.nginx.org/pipermail/nginx-devel/2023-September/NUL3Y2FPPFSHMPTFTL65KXSXNTX3NQMK.html
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 18 Oct 2023 04:30:11 +0300 |
parents | d620f497c50f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_CRC_H_INCLUDED_ #define _NGX_CRC_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> /* 32-bit crc16 */ static ngx_inline uint32_t ngx_crc(u_char *data, size_t len) { uint32_t sum; for (sum = 0; len; len--) { /* * gcc 2.95.2 x86 and icc 7.1.006 compile * that operator into the single "rol" opcode, * msvc 6.0sp2 compiles it into four opcodes. */ sum = sum >> 1 | sum << 31; sum += *data++; } return sum; } #endif /* _NGX_CRC_H_INCLUDED_ */