From 8e8f98c9d46788438bd176f7c2bfde0a5837cad9 Mon Sep 17 00:00:00 2001 From: Dave Barach Date: Fri, 3 Feb 2017 11:58:53 -0500 Subject: Wheel-timer infra Change-Id: I5499dd6b768425a56936afae50bd578620c83d30 Signed-off-by: Dave Barach --- src/vppinfra/tw_timer_template.h | 199 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 199 insertions(+) create mode 100644 src/vppinfra/tw_timer_template.h (limited to 'src/vppinfra/tw_timer_template.h') diff --git a/src/vppinfra/tw_timer_template.h b/src/vppinfra/tw_timer_template.h new file mode 100644 index 00000000000..cf15ab8a667 --- /dev/null +++ b/src/vppinfra/tw_timer_template.h @@ -0,0 +1,199 @@ +/* + * Copyright (c) 2016 Cisco and/or its affiliates. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef TW_SUFFIX +#error do not include tw_timer_template.h directly +#endif + +#include +#include + +#ifndef _twt +#define _twt(a,b) a##b##_t +#define __twt(a,b) _twt(a,b) +#define TWT(a) __twt(a,TW_SUFFIX) + +#define _tw(a,b) a##b +#define __tw(a,b) _tw(a,b) +#define TW(a) __tw(a,TW_SUFFIX) +#endif + +/** @file + @brief TW timer template header file, do not compile directly + +Instantiation of tw_timer_template.h generates named structures to +implement specific timer wheel geometries. Choices include: number of +timer wheels (currently, 1 or 2), number of slots per ring (a power of +two), and the number of timers per "object handle". + +Internally, user object/timer handles are 32-bit integers, so if one +selects 16 timers/object (4 bits), the resulting timer wheel handle is +limited to 2**28 objects. + +Here are the specific settings required to generate a single 2048 slot +wheel which supports 2 timers per object: + + #define TW_TIMER_WHEELS 1 + #define TW_SLOTS_PER_RING 2048 + #define TW_RING_SHIFT 11 + #define TW_RING_MASK (TW_SLOTS_PER_RING -1) + #define TW_TIMERS_PER_OBJECT 2 + #define LOG2_TW_TIMERS_PER_OBJECT 1 + #define TW_SUFFIX _2t_1w_2048sl + +See tw_timer_2t_1w_2048sl.h for a complete +example. + +tw_timer_template.h is not intended to be #included directly. Client +codes can include multiple timer geometry header files, although +extreme caution would required to use the TW and TWT macros in such a +case. + +API usage example: + +Initialize a two-timer, single 2048-slot wheel w/ a 1-second +timer granularity: + + tw_timer_wheel_init_2t_1w_2048sl (&tm->single_wheel, + expired_timer_single_callback, + 1.0 / * timer interval * / ); + +Start a timer: + + handle = tw_timer_start_2t_1w_2048sl (&tm->single_wheel, elt_index, + [0 | 1] / * timer id * / , + expiration_time_in_u32_ticks); + +Stop a timer: + + tw_timer_stop_2t_1w_2048sl (&tm->single_wheel, handle); + +Expired timer callback: + + static void + expired_timer_single_callback (u32 * expired_timers) + { + int i; + u32 pool_index, timer_id; + tw_timer_test_elt_t *e; + tw_timer_test_main_t *tm = &tw_timer_test_main; + + for (i = 0; i < vec_len (expired_timers); + { + pool_index = expired_timers[i] & 0x7FFFFFFF; + timer_id = expired_timers[i] >> 31; + + ASSERT (timer_id == 1); + + e = pool_elt_at_index (tm->test_elts, pool_index); + + if (e->expected_to_expire != tm->single_wheel.current_tick) + { + fformat (stdout, "[%d] expired at %d not %d\n", + e - tm->test_elts, tm->single_wheel.current_tick, + e->expected_to_expire); + } + pool_put (tm->test_elts, e); + } + } + */ + +typedef struct +{ + /** next, previous pool indices */ + u32 next; + u32 prev; +#if TW_TIMER_WHEELS > 0 + /** fast ring offset, only valid in the slow ring */ + u16 fast_ring_offset; + u16 pad; +#endif + /** user timer handle */ + u32 user_handle; +} TWT (tw_timer); + +/* + * These structures ar used by all geometries, + * so they need a private #include block... + */ +#ifndef __defined_tw_timer_wheel_slot__ +#define __defined_tw_timer_wheel_slot__ +typedef struct +{ + /** Listhead of timers which expire in this interval */ + u32 head_index; +} tw_timer_wheel_slot_t; +typedef enum +{ + /** Fast timer ring ID */ + TW_TIMER_RING_FAST, + /** Slow timer ring ID */ + TW_TIMER_RING_SLOW, +} tw_ring_index_t; +#endif /* __defined_tw_timer_wheel_slot__ */ + +typedef struct +{ + /** Timer pool */ + TWT (tw_timer) * timers; + + /** Next time the wheel should run */ + f64 next_run_time; + + /** Last time the wheel ran */ + f64 last_run_time; + + /** Timer ticks per second */ + f64 ticks_per_second; + + /** Timer interval, also needed to avoid fp divide in speed path */ + f64 timer_interval; + + /** current tick */ + u32 current_tick; + + /** current wheel indices */ + u32 current_index[TW_TIMER_WHEELS]; + + /** wheel arrays */ + tw_timer_wheel_slot_t w[TW_TIMER_WHEELS][TW_SLOTS_PER_RING]; + + /** expired timer callback, receives a vector of handles */ + void (*expired_timer_callback) (u32 * expired_timer_handles); + + /** vector of expired timers */ + u32 *expired_timer_handles; +} TWT (tw_timer_wheel); + +u32 TW (tw_timer_start) (TWT (tw_timer_wheel) * tw, + u32 pool_index, u32 timer_id, u32 interval); + +void TW (tw_timer_stop) (TWT (tw_timer_wheel) * tw, u32 handle); + +void TW (tw_timer_wheel_init) (TWT (tw_timer_wheel) * tw, + void *expired_timer_callback, + f64 timer_interval); + +void TW (tw_timer_wheel_free) (TWT (tw_timer_wheel) * tw); + +void TW (tw_timer_expire_timers) (TWT (tw_timer_wheel) * tw, f64 now); + +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ -- cgit 1.2.3-korg