CLEANUP: server: reorder some fields in the server struct to respect cache lines
There's currently quite some thread contention in the server struct
because frequently fields accessed fields are mixed with those being
often written to by any thread. Let's split this a little bit to
separate a few areas:
- pure config / admin / operating status (almost never changes)
- idle and queuing (fast changes, done almost together)
- LB (fast changes, not necessarily dependent on the above)
- counters (fast changes, at a different instant again)
diff --git a/include/haproxy/server-t.h b/include/haproxy/server-t.h
index ad3a40f..e59ba4d 100644
--- a/include/haproxy/server-t.h
+++ b/include/haproxy/server-t.h
@@ -213,10 +213,12 @@
struct proxy;
struct server {
+ /* mostly config or admin stuff, doesn't change often */
enum obj_type obj_type; /* object type == OBJ_TYPE_SERVER */
enum srv_state next_state, cur_state; /* server state among SRV_ST_* */
enum srv_admin next_admin, cur_admin; /* server maintenance status : SRV_ADMF_* */
signed char use_ssl; /* ssl enabled (1: on, 0: disabled, -1 forced off) */
+ unsigned int flags; /* server flags (SRV_F_*) */
unsigned int pp_opts; /* proxy protocol options (SRV_PP_*) */
struct list global_list; /* attach point in the global servers_list */
struct server *next;
@@ -227,45 +229,24 @@
struct proxy *proxy; /* the proxy this server belongs to */
const struct mux_proto_list *mux_proto; /* the mux to use for all outgoing connections (specified by the "proto" keyword) */
- int served; /* # of active sessions currently being served (ie not pending) */
- int cur_sess; /* number of currently active sessions (including syn_sent) */
unsigned maxconn, minconn; /* max # of active sessions (0 = unlimited), min# for dynamic limit. */
- int nbpend; /* number of pending connections */
- unsigned int queue_idx; /* count of pending connections which have been de-queued */
- int maxqueue; /* maximum number of pending connections allowed */
- struct freq_ctr sess_per_sec; /* sessions per second on this server */
- struct be_counters counters; /* statistics counters */
-
- struct eb_root pendconns; /* pending connections */
struct srv_per_thread *per_thr; /* array of per-thread stuff such as connections lists */
+ unsigned int *curr_idle_thr; /* Current number of orphan idling connections per thread */
+
unsigned int pool_purge_delay; /* Delay before starting to purge the idle conns pool */
unsigned int low_idle_conns; /* min idle connection count to start picking from other threads */
unsigned int max_idle_conns; /* Max number of connection allowed in the orphan connections list */
- unsigned int curr_idle_conns; /* Current number of orphan idling connections, both the idle and the safe lists */
- unsigned int curr_idle_nb; /* Current number of connections in the idle list */
- unsigned int curr_safe_nb; /* Current number of connections in the safe list */
- unsigned int curr_used_conns; /* Current number of used connections */
- unsigned int max_used_conns; /* Max number of used connections (the counter is reset at each connection purges */
- unsigned int est_need_conns; /* Estimate on the number of needed connections (max of curr and previous max_used) */
- unsigned int next_takeover; /* thread ID to try to steal connections from next time */
- unsigned int *curr_idle_thr; /* Current number of orphan idling connections per thread */
int max_reuse; /* Max number of requests on a same connection */
- __decl_thread(HA_SPINLOCK_T lock); /* may enclose the proxy's lock, must not be taken under */
- struct eb32_node idle_node; /* When to next do cleanup in the idle connections */
struct task *warmup; /* the task dedicated to the warmup when slowstart is set */
- struct conn_src conn_src; /* connection source settings */
-
struct server *track; /* the server we're currently tracking, if any */
struct server *trackers; /* the list of servers tracking us, if any */
struct server *tracknext; /* next server tracking <track> in <track>'s trackers list */
char *trackit; /* temporary variable to make assignment deferrable */
- int consecutive_errors; /* current number of consecutive errors */
int consecutive_errors_limit; /* number of consecutive errors that triggers an event */
short observe, onerror; /* observing mode: one of HANA_OBS_*; what to do on error: on of ANA_ONERR_* */
short onmarkeddown; /* what to do when marked down: one of HANA_ONMARKEDDOWN_* */
short onmarkedup; /* what to do when marked up: one of HANA_ONMARKEDUP_* */
- unsigned int flags; /* server flags (SRV_F_*) */
int slowstart; /* slowstart time in seconds (ms in the conf) */
char *id; /* just for identification */
@@ -274,17 +255,51 @@
unsigned next_eweight; /* next pending eweight to commit */
unsigned rweight; /* remainder of weight in the current LB tree */
unsigned cumulative_weight; /* weight of servers prior to this one in the same group, for chash balancing */
- unsigned npos, lpos; /* next and last positions in the LB tree */
+ int maxqueue; /* maximum number of pending connections allowed */
+
+ /* The elements below may be changed on every single request by any
+ * thread, and generally at the same time.
+ */
+ ALWAYS_ALIGN(64);
+ struct eb32_node idle_node; /* When to next do cleanup in the idle connections */
+ unsigned int curr_idle_conns; /* Current number of orphan idling connections, both the idle and the safe lists */
+ unsigned int curr_idle_nb; /* Current number of connections in the idle list */
+ unsigned int curr_safe_nb; /* Current number of connections in the safe list */
+ unsigned int curr_used_conns; /* Current number of used connections */
+ unsigned int max_used_conns; /* Max number of used connections (the counter is reset at each connection purges */
+ unsigned int est_need_conns; /* Estimate on the number of needed connections (max of curr and previous max_used) */
+ unsigned int next_takeover; /* thread ID to try to steal connections from next time */
+
+ struct eb_root pendconns; /* pending connections */
+
+ /* Element below are usd by LB algorithms and must be doable in
+ * parallel to other threads reusing connections above.
+ */
+ ALWAYS_ALIGN(64);
+ __decl_thread(HA_SPINLOCK_T lock); /* may enclose the proxy's lock, must not be taken under */
+ unsigned npos, lpos; /* next and last positions in the LB tree, protected by LB lock */
struct eb32_node lb_node; /* node used for tree-based load balancing */
- struct eb_root *lb_tree; /* we want to know in what tree the server is */
struct server *next_full; /* next server in the temporary full list */
+
+ /* usually atomically updated by any thread during parsing or on end of request */
+ ALWAYS_ALIGN(64);
+ int cur_sess; /* number of currently active sessions (including syn_sent) */
+ int served; /* # of active sessions currently being served (ie not pending) */
+ int nbpend; /* number of pending connections */
+ int consecutive_errors; /* current number of consecutive errors */
+ struct freq_ctr sess_per_sec; /* sessions per second on this server */
+ unsigned int queue_idx; /* count of pending connections which have been de-queued */
+ struct be_counters counters; /* statistics counters */
+
+ /* Below are some relatively stable settings, only changed under the lock */
+ ALWAYS_ALIGN(64);
+
+ struct eb_root *lb_tree; /* we want to know in what tree the server is */
+ struct tree_occ *lb_nodes; /* lb_nodes_tot * struct tree_occ */
unsigned lb_nodes_tot; /* number of allocated lb_nodes (C-HASH) */
unsigned lb_nodes_now; /* number of lb_nodes placed in the tree (C-HASH) */
- struct tree_occ *lb_nodes; /* lb_nodes_tot * struct tree_occ */
const struct netns_entry *netns; /* contains network namespace name or NULL. Network namespace comes from configuration */
- /* warning, these structs are huge, keep them at the bottom */
- struct sockaddr_storage addr; /* the address to connect to, doesn't include the port */
struct xprt_ops *xprt; /* transport-layer operations */
unsigned int svc_port; /* the port to connect to (for relevant families) */
unsigned down_time; /* total time the server was down */
@@ -372,6 +387,9 @@
} op_st_chg; /* operational status change's reason */
char adm_st_chg_cause[48]; /* administrative status change's cause */
+ /* warning, these structs are huge, keep them at the bottom */
+ struct conn_src conn_src; /* connection source settings */
+ struct sockaddr_storage addr; /* the address to connect to, doesn't include the port */
struct sockaddr_storage socks4_addr; /* the address of the SOCKS4 Proxy, including the port */
EXTRA_COUNTERS(extra_counters);