haproxy/include/types/global.h
Willy Tarreau beb859abce MINOR: polling: add an option to support busy polling
In some situations, especially when dealing with low latency on processors
supporting a variable frequency or when running inside virtual machines,
each time the process waits for an I/O using the poller, the processor
goes back to sleep or is offered to another VM for a long time, and it
causes excessively high latencies.

A solution to this provided by this patch is to enable busy polling using
a global option. When busy polling is enabled, the pollers never sleep and
loop over themselves waiting for an I/O event to happen or for a timeout
to occur. On multi-processor machines it can significantly overheat the
processor but it usually results in much lower latencies.

A typical test consisting in injecting traffic over a single connection at
a time over the loopback shows a bump from 4640 to 8540 connections per
second on forwarded connections, indicating a latency reduction of 98
microseconds for each connection, and a bump from 12500 to 21250 for
locally terminated connections (redirects), indicating a reduction of
33 microseconds.

It is only usable with epoll and kqueue because select() and poll()'s
API is not convenient for such usages, and the level of performance they
are used in doesn't benefit from this anyway.

The option, which obviously remains disabled by default, can be turned
on using "busy-polling" in the global section, and turned off later
using "no busy-polling". Its status is reported in "show info" to help
troubleshooting suspicious CPU spikes.
2018-11-22 19:47:30 +01:00

256 lines
9.7 KiB
C

/*
* include/types/global.h
* Global variables.
*
* Copyright (C) 2000-2012 Willy Tarreau - w@1wt.eu
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, version 2.1
* exclusively.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _TYPES_GLOBAL_H
#define _TYPES_GLOBAL_H
#include <netinet/in.h>
#include <common/config.h>
#include <common/standard.h>
#include <common/hathreads.h>
#include <types/listener.h>
#include <types/proxy.h>
#include <types/task.h>
#include <types/vars.h>
#ifndef UNIX_MAX_PATH
#define UNIX_MAX_PATH 108
#endif
/* modes of operation (global.mode) */
#define MODE_DEBUG 0x01
#define MODE_DAEMON 0x02
#define MODE_QUIET 0x04
#define MODE_CHECK 0x08
#define MODE_VERBOSE 0x10
#define MODE_STARTING 0x20
#define MODE_FOREGROUND 0x40
#define MODE_MWORKER 0x80 /* Master Worker */
#define MODE_MWORKER_WAIT 0x100 /* Master Worker wait mode */
/* list of last checks to perform, depending on config options */
#define LSTCHK_CAP_BIND 0x00000001 /* check that we can bind to any port */
#define LSTCHK_NETADM 0x00000002 /* check that we have CAP_NET_ADMIN */
/* Global tuning options */
/* available polling mechanisms */
#define GTUNE_USE_SELECT (1<<0)
#define GTUNE_USE_POLL (1<<1)
#define GTUNE_USE_EPOLL (1<<2)
#define GTUNE_USE_KQUEUE (1<<3)
/* platform-specific options */
#define GTUNE_USE_SPLICE (1<<4)
#define GTUNE_USE_GAI (1<<5)
#define GTUNE_USE_REUSEPORT (1<<6)
#define GTUNE_RESOLVE_DONTFAIL (1<<7)
#define GTUNE_SOCKET_TRANSFER (1<<8)
#define GTUNE_NOEXIT_ONFAILURE (1<<9)
#define GTUNE_USE_SYSTEMD (1<<10)
#define GTUNE_BUSY_POLLING (1<<11)
/* Access level for a stats socket */
#define ACCESS_LVL_NONE 0
#define ACCESS_LVL_USER 1
#define ACCESS_LVL_OPER 2
#define ACCESS_LVL_ADMIN 3
#define ACCESS_LVL_MASK 0x3
#define ACCESS_FD_LISTENERS 0x4 /* expose listeners FDs on stats socket */
#define ACCESS_MASTER 0x8 /* works with the master (and every other processes) */
#define ACCESS_MASTER_ONLY 0x10 /* only works with the worker */
/* SSL server verify mode */
enum {
SSL_SERVER_VERIFY_NONE = 0,
SSL_SERVER_VERIFY_REQUIRED = 1,
};
/* FIXME : this will have to be redefined correctly */
struct global {
int uid;
int gid;
int external_check;
int nbproc;
int nbthread;
unsigned int hard_stop_after; /* maximum time allowed to perform a soft-stop */
int maxconn, hardmaxconn;
int maxsslconn;
int ssl_session_max_cost; /* how many bytes an SSL session may cost */
int ssl_handshake_max_cost; /* how many bytes an SSL handshake may use */
int ssl_used_frontend; /* non-zero if SSL is used in a frontend */
int ssl_used_backend; /* non-zero if SSL is used in a backend */
int ssl_used_async_engines; /* number of used async engines */
unsigned int ssl_server_verify; /* default verify mode on servers side */
struct freq_ctr conn_per_sec;
struct freq_ctr sess_per_sec;
struct freq_ctr ssl_per_sec;
struct freq_ctr ssl_fe_keys_per_sec;
struct freq_ctr ssl_be_keys_per_sec;
struct freq_ctr comp_bps_in; /* bytes per second, before http compression */
struct freq_ctr comp_bps_out; /* bytes per second, after http compression */
int cps_lim, cps_max;
int sps_lim, sps_max;
int ssl_lim, ssl_max;
int ssl_fe_keys_max, ssl_be_keys_max;
unsigned int shctx_lookups, shctx_misses;
int comp_rate_lim; /* HTTP compression rate limit */
int maxpipes; /* max # of pipes */
int maxsock; /* max # of sockets */
int rlimit_nofile; /* default ulimit-n value : 0=unset */
int rlimit_memmax_all; /* default all-process memory limit in megs ; 0=unset */
int rlimit_memmax; /* default per-process memory limit in megs ; 0=unset */
long maxzlibmem; /* max RAM for zlib in bytes */
int mode;
unsigned int req_count; /* request counter (HTTP or TCP session) for logs and unique_id */
int last_checks;
int spread_checks;
int max_spread_checks;
int max_syslog_len;
char *chroot;
char *pidfile;
char *node, *desc; /* node name & description */
struct buffer log_tag; /* name for syslog */
struct list logsrvs;
char *log_send_hostname; /* set hostname in syslog header */
char *server_state_base; /* path to a directory where server state files can be found */
char *server_state_file; /* path to the file where server states are loaded from */
struct {
int maxpollevents; /* max number of poll events at once */
int maxaccept; /* max number of consecutive accept() */
int options; /* various tuning options */
int runqueue_depth;/* max number of tasks to run at once */
int recv_enough; /* how many input bytes at once are "enough" */
int bufsize; /* buffer size in bytes, defaults to BUFSIZE */
int maxrewrite; /* buffer max rewrite size in bytes, defaults to MAXREWRITE */
int reserved_bufs; /* how many buffers can only be allocated for response */
int buf_limit; /* if not null, how many total buffers may only be allocated */
int client_sndbuf; /* set client sndbuf to this value if not null */
int client_rcvbuf; /* set client rcvbuf to this value if not null */
int server_sndbuf; /* set server sndbuf to this value if not null */
int server_rcvbuf; /* set server rcvbuf to this value if not null */
int chksize; /* check buffer size in bytes, defaults to BUFSIZE */
int pipesize; /* pipe size in bytes, system defaults if zero */
int max_http_hdr; /* max number of HTTP headers, use MAX_HTTP_HDR if zero */
int requri_len; /* max len of request URI, use REQURI_LEN if zero */
int cookie_len; /* max length of cookie captures */
int pattern_cache; /* max number of entries in the pattern cache. */
int sslcachesize; /* SSL cache size in session, defaults to 20000 */
int comp_maxlevel; /* max HTTP compression level */
unsigned short idle_timer; /* how long before an empty buffer is considered idle (ms) */
} tune;
struct {
char *prefix; /* path prefix of unix bind socket */
struct { /* UNIX socket permissions */
uid_t uid; /* -1 to leave unchanged */
gid_t gid; /* -1 to leave unchanged */
mode_t mode; /* 0 to leave unchanged */
} ux;
} unix_bind;
struct proxy *stats_fe; /* the frontend holding the stats settings */
struct vars vars; /* list of variables for the process scope. */
#ifdef USE_CPU_AFFINITY
struct {
unsigned long proc[LONGBITS]; /* list of CPU masks for the 32/64 first processes */
unsigned long thread[LONGBITS][MAX_THREADS]; /* list of CPU masks for the 32/64 first threads per process */
} cpu_map;
#endif
};
/*
* Structure used to describe the processes in master worker mode
*/
struct mworker_proc {
int pid;
char type; /* m(aster), w(orker) */
/* 3 bytes hole here */
int ipc_fd[2]; /* 0 is master side, 1 is worker side */
int relative_pid;
int reloads;
int timestamp;
struct server *srv; /* the server entry in the master proxy */
struct list list;
};
extern struct global global;
extern int pid; /* current process id */
extern int relative_pid; /* process id starting at 1 */
extern unsigned long pid_bit; /* bit corresponding to the process id */
extern int actconn; /* # of active sessions */
extern int listeners;
extern int jobs; /* # of active jobs (listeners, sessions, open devices) */
extern int unstoppable_jobs; /* # of active jobs that can't be stopped during a soft stop */
extern int active_peers; /* # of active peers (connection attempts and successes) */
extern int connected_peers; /* # of really connected peers */
extern THREAD_LOCAL struct buffer trash;
extern int nb_oldpids; /* contains the number of old pids found */
extern const int zero;
extern const int one;
extern const struct linger nolinger;
extern int stopping; /* non zero means stopping in progress */
extern int killed; /* non zero means a hard-stop is triggered */
extern char hostname[MAX_HOSTNAME_LEN];
extern char localpeer[MAX_HOSTNAME_LEN];
extern struct list global_listener_queue; /* list of the temporarily limited listeners */
extern struct task *global_listener_queue_task;
extern unsigned int warned; /* bitfield of a few warnings to emit just once */
extern volatile unsigned long sleeping_thread_mask;
extern struct list proc_list; /* list of process in mworker mode */
extern struct mworker_proc *proc_self; /* process structure of current process */
/* bit values to go with "warned" above */
#define WARN_BLOCK_DEPRECATED 0x00000001
/* unassigned : 0x00000002 */
#define WARN_REDISPATCH_DEPRECATED 0x00000004
#define WARN_CLITO_DEPRECATED 0x00000008
#define WARN_SRVTO_DEPRECATED 0x00000010
#define WARN_CONTO_DEPRECATED 0x00000020
/* to be used with warned and WARN_* */
static inline int already_warned(unsigned int warning)
{
if (warned & warning)
return 1;
warned |= warning;
return 0;
}
void deinit(void);
void hap_register_build_opts(const char *str, int must_free);
void hap_register_post_check(int (*fct)());
void hap_register_post_deinit(void (*fct)());
void hap_register_per_thread_init(int (*fct)());
void hap_register_per_thread_deinit(void (*fct)());
void mworker_accept_wrapper(int fd);
#endif /* _TYPES_GLOBAL_H */
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/