Mercurial > hg > nginx
view src/core/ngx_array.c @ 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 | 4fef8ed52389 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> ngx_array_t * ngx_array_create(ngx_pool_t *p, ngx_uint_t n, size_t size) { ngx_array_t *a; a = ngx_palloc(p, sizeof(ngx_array_t)); if (a == NULL) { return NULL; } if (ngx_array_init(a, p, n, size) != NGX_OK) { return NULL; } return a; } void ngx_array_destroy(ngx_array_t *a) { ngx_pool_t *p; p = a->pool; if ((u_char *) a->elts + a->size * a->nalloc == p->d.last) { p->d.last -= a->size * a->nalloc; } if ((u_char *) a + sizeof(ngx_array_t) == p->d.last) { p->d.last = (u_char *) a; } } void * ngx_array_push(ngx_array_t *a) { void *elt, *new; size_t size; ngx_pool_t *p; if (a->nelts == a->nalloc) { /* the array is full */ size = a->size * a->nalloc; p = a->pool; if ((u_char *) a->elts + size == p->d.last && p->d.last + a->size <= p->d.end) { /* * the array allocation is the last in the pool * and there is space for new allocation */ p->d.last += a->size; a->nalloc++; } else { /* allocate a new array */ new = ngx_palloc(p, 2 * size); if (new == NULL) { return NULL; } ngx_memcpy(new, a->elts, size); a->elts = new; a->nalloc *= 2; } } elt = (u_char *) a->elts + a->size * a->nelts; a->nelts++; return elt; } void * ngx_array_push_n(ngx_array_t *a, ngx_uint_t n) { void *elt, *new; size_t size; ngx_uint_t nalloc; ngx_pool_t *p; size = n * a->size; if (a->nelts + n > a->nalloc) { /* the array is full */ p = a->pool; if ((u_char *) a->elts + a->size * a->nalloc == p->d.last && p->d.last + size <= p->d.end) { /* * the array allocation is the last in the pool * and there is space for new allocation */ p->d.last += size; a->nalloc += n; } else { /* allocate a new array */ nalloc = 2 * ((n >= a->nalloc) ? n : a->nalloc); new = ngx_palloc(p, nalloc * a->size); if (new == NULL) { return NULL; } ngx_memcpy(new, a->elts, a->nelts * a->size); a->elts = new; a->nalloc = nalloc; } } elt = (u_char *) a->elts + a->size * a->nelts; a->nelts += n; return elt; }