Mercurial > hg > nginx
view src/os/unix/ngx_process.h @ 7583:efd71d49bde0
Events: available bytes calculation via ioctl(FIONREAD).
This makes it possible to avoid looping for a long time while working
with a fast enough peer when data are added to the socket buffer faster
than we are able to read and process them (ticket #1431). This is
basically what we already do on FreeBSD with kqueue, where information
about the number of bytes in the socket buffer is returned by
the kevent() call.
With other event methods rev->available is now set to -1 when the socket
is ready for reading. Later in ngx_recv() and ngx_recv_chain(), if
full buffer is received, real number of bytes in the socket buffer is
retrieved using ioctl(FIONREAD). Reading more than this number of bytes
ensures that even with edge-triggered event methods the event will be
triggered again, so it is safe to stop processing of the socket and
switch to other connections.
Using ioctl(FIONREAD) only after reading a full buffer is an optimization.
With this approach we only call ioctl(FIONREAD) when there are at least
two recv()/readv() calls.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 17 Oct 2019 16:02:19 +0300 |
parents | 8b84d60ef13d |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_PROCESS_H_INCLUDED_ #define _NGX_PROCESS_H_INCLUDED_ #include <ngx_setaffinity.h> #include <ngx_setproctitle.h> typedef pid_t ngx_pid_t; #define NGX_INVALID_PID -1 typedef void (*ngx_spawn_proc_pt) (ngx_cycle_t *cycle, void *data); typedef struct { ngx_pid_t pid; int status; ngx_socket_t channel[2]; ngx_spawn_proc_pt proc; void *data; char *name; unsigned respawn:1; unsigned just_spawn:1; unsigned detached:1; unsigned exiting:1; unsigned exited:1; } ngx_process_t; typedef struct { char *path; char *name; char *const *argv; char *const *envp; } ngx_exec_ctx_t; #define NGX_MAX_PROCESSES 1024 #define NGX_PROCESS_NORESPAWN -1 #define NGX_PROCESS_JUST_SPAWN -2 #define NGX_PROCESS_RESPAWN -3 #define NGX_PROCESS_JUST_RESPAWN -4 #define NGX_PROCESS_DETACHED -5 #define ngx_getpid getpid #define ngx_getppid getppid #ifndef ngx_log_pid #define ngx_log_pid ngx_pid #endif ngx_pid_t ngx_spawn_process(ngx_cycle_t *cycle, ngx_spawn_proc_pt proc, void *data, char *name, ngx_int_t respawn); ngx_pid_t ngx_execute(ngx_cycle_t *cycle, ngx_exec_ctx_t *ctx); ngx_int_t ngx_init_signals(ngx_log_t *log); void ngx_debug_point(void); #if (NGX_HAVE_SCHED_YIELD) #define ngx_sched_yield() sched_yield() #else #define ngx_sched_yield() usleep(1) #endif extern int ngx_argc; extern char **ngx_argv; extern char **ngx_os_argv; extern ngx_pid_t ngx_pid; extern ngx_pid_t ngx_parent; extern ngx_socket_t ngx_channel; extern ngx_int_t ngx_process_slot; extern ngx_int_t ngx_last_process; extern ngx_process_t ngx_processes[NGX_MAX_PROCESSES]; #endif /* _NGX_PROCESS_H_INCLUDED_ */