1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
//! This module provide functions for find all required synchronizations (barriers and semaphores).
//!

use std::collections::HashMap;
use std::ops::{Range, RangeFrom, RangeTo};

use crate::{
    chain::{Chain, Link},
    collect::Chains,
    node::State,
    resource::{AccessFlags, Buffer, Image, Resource},
    schedule::{Queue, QueueId, Schedule, SubmissionId},
    Id,
};

/// Semaphore identifier.
/// It allows to distinguish different semaphores to be later replaced in `Signal`s and `Wait`s
/// for references to semaphores (or tokens associated with real semaphores).
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct Semaphore {
    id: Id,
    points: Range<SubmissionId>,
}

impl Semaphore {
    fn new(id: Id, points: Range<SubmissionId>) -> Self {
        Semaphore { id, points }
    }
}

/// Semaphore signal info.
/// There must be paired wait.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub struct Signal<S>(S);

impl<S> Signal<S> {
    /// Create signaling for specified point.
    /// At this point `Wait` must be created as well.
    /// `id` and `point` combination must be unique.
    fn new(semaphore: S) -> Self {
        Signal(semaphore)
    }

    /// Get semaphore of the `Signal`.
    pub fn semaphore(&self) -> &S {
        &self.0
    }
}

/// Semaphore wait info.
/// There must be paired signal.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub struct Wait<S>(S, gfx_hal::pso::PipelineStage);

impl<S> Wait<S> {
    /// Create waiting for specified point.
    /// At this point `Signal` must be created as well.
    /// `id` and `point` combination must be unique.
    fn new(semaphore: S, stages: gfx_hal::pso::PipelineStage) -> Self {
        Wait(semaphore, stages)
    }

    /// Get semaphore of the `Wait`.
    pub fn semaphore(&self) -> &S {
        &self.0
    }

    /// Stage at which to wait.
    pub fn stage(&self) -> gfx_hal::pso::PipelineStage {
        self.1
    }
}

/// Pipeline barrier info.
#[derive(Clone, Debug)]
pub struct Barrier<R: Resource> {
    /// `Some` queue for ownership transfer. Or `None`
    pub families: Option<Range<gfx_hal::queue::QueueFamilyId>>,

    /// State transition.
    pub states: Range<(R::Access, R::Layout, gfx_hal::pso::PipelineStage)>,
}

impl<R> Barrier<R>
where
    R: Resource,
{
    fn new(states: Range<State<R>>) -> Self {
        Barrier {
            families: None,
            states: (
                states.start.access,
                states.start.layout,
                states.start.stages,
            )..(states.end.access, states.end.layout, states.end.stages),
        }
    }

    fn transfer(
        families: Range<gfx_hal::queue::QueueFamilyId>,
        states: Range<(R::Access, R::Layout)>,
    ) -> Self {
        Barrier {
            families: Some(families),
            states: (
                states.start.0,
                states.start.1,
                gfx_hal::pso::PipelineStage::TOP_OF_PIPE,
            )
                ..(
                    states.end.0,
                    states.end.1,
                    gfx_hal::pso::PipelineStage::BOTTOM_OF_PIPE,
                ),
        }
    }

    fn acquire(
        families: Range<gfx_hal::queue::QueueFamilyId>,
        left: RangeFrom<R::Layout>,
        right: RangeTo<(R::Access, R::Layout)>,
    ) -> Self {
        Self::transfer(
            families,
            (R::Access::empty(), left.start)..(right.end.0, right.end.1),
        )
    }

    fn release(
        families: Range<gfx_hal::queue::QueueFamilyId>,
        left: RangeFrom<(R::Access, R::Layout)>,
        right: RangeTo<R::Layout>,
    ) -> Self {
        Self::transfer(
            families,
            (left.start.0, left.start.1)..(R::Access::empty(), right.end),
        )
    }
}

/// Map of barriers by resource id.
pub type Barriers<R> = HashMap<Id, Barrier<R>>;

/// Map of barriers by buffer id.
pub type BufferBarriers = Barriers<Buffer>;

/// Map of barriers by image id.
pub type ImageBarriers = Barriers<Image>;

/// Synchronization for submission at one side.
#[derive(Clone, Debug)]
pub struct Guard {
    /// Buffer pipeline barriers to be inserted before or after (depends on the side) commands of the submission.
    pub buffers: BufferBarriers,

    /// Image pipeline barriers to be inserted before or after (depends on the side) commands of the submission.
    pub images: ImageBarriers,
}

impl Guard {
    fn new() -> Self {
        Guard {
            buffers: HashMap::default(),
            images: HashMap::default(),
        }
    }

    fn pick<R: Resource>(&mut self) -> &mut Barriers<R> {
        use std::any::Any;
        let Guard {
            ref mut buffers,
            ref mut images,
        } = *self;
        Any::downcast_mut(buffers)
            .or_else(move || Any::downcast_mut(images))
            .expect("`R` should be `Buffer` or `Image`")
    }
}

/// Both sides of synchronization for submission.
#[derive(Clone, Debug)]
pub struct SyncData<S, W> {
    /// Points at other queues that must be waited before commands from the submission can be executed.
    pub wait: Vec<Wait<W>>,

    /// Acquire side of submission synchronization.
    /// Synchronization commands from this side must be recorded before main commands of submission.
    pub acquire: Guard,

    /// Release side of submission synchronization.
    /// Synchronization commands from this side must be recorded after main commands of submission.
    pub release: Guard,

    /// Points at other queues that can run after barriers above.
    pub signal: Vec<Signal<S>>,
}

impl<S, W> SyncData<S, W> {
    fn new() -> Self {
        SyncData {
            wait: Vec::new(),
            acquire: Guard::new(),
            release: Guard::new(),
            signal: Vec::new(),
        }
    }

    fn convert_signal<F, T>(self, mut f: F) -> SyncData<T, W>
    where
        F: FnMut(S) -> T,
    {
        SyncData {
            wait: self.wait,
            acquire: Guard {
                buffers: self.acquire.buffers,
                images: self.acquire.images,
            },
            release: Guard {
                buffers: self.release.buffers,
                images: self.release.images,
            },
            signal: self
                .signal
                .into_iter()
                .map(|Signal(semaphore)| Signal(f(semaphore)))
                .collect(),
        }
    }

    fn convert_wait<F, T>(self, mut f: F) -> SyncData<S, T>
    where
        F: FnMut(W) -> T,
    {
        SyncData {
            wait: self
                .wait
                .into_iter()
                .map(|Wait(semaphore, stage)| Wait(f(semaphore), stage))
                .collect(),
            acquire: Guard {
                buffers: self.acquire.buffers,
                images: self.acquire.images,
            },
            release: Guard {
                buffers: self.release.buffers,
                images: self.release.images,
            },
            signal: self.signal,
        }
    }
}

struct SyncTemp(HashMap<SubmissionId, SyncData<Semaphore, Semaphore>>);
impl SyncTemp {
    fn get_sync(&mut self, sid: SubmissionId) -> &mut SyncData<Semaphore, Semaphore> {
        self.0.entry(sid).or_insert_with(|| SyncData::new())
    }
}

/// Find required synchronization for all submissions in `Chains`.
pub fn sync<F, S, W>(chains: &Chains, mut new_semaphore: F) -> Schedule<SyncData<S, W>>
where
    F: FnMut() -> (S, W),
{
    let ref schedule = chains.schedule;
    let ref buffers = chains.buffers;
    let ref images = chains.images;

    let mut sync = SyncTemp(HashMap::default());
    for (&id, chain) in buffers {
        sync_chain(id, chain, schedule, &mut sync);
    }
    for (&id, chain) in images {
        sync_chain(id, chain, schedule, &mut sync);
    }
    if schedule.queue_count() > 1 {
        optimize(schedule, &mut sync);
    }

    let mut result = Schedule::new();
    let mut signals: HashMap<Semaphore, Option<S>> = HashMap::default();
    let mut waits: HashMap<Semaphore, Option<W>> = HashMap::default();

    for queue in schedule.iter().flat_map(|family| family.iter()) {
        let mut new_queue = Queue::new(queue.id());
        for submission in queue.iter() {
            let sync = if let Some(sync) = sync.0.remove(&submission.id()) {
                let sync = sync.convert_signal(|semaphore| match signals.get_mut(&semaphore) {
                    None => {
                        let (signal, wait) = new_semaphore();
                        let old = waits.insert(semaphore, Some(wait));
                        assert!(old.is_none());
                        signal
                    }
                    Some(signal) => signal.take().unwrap(),
                });
                let sync = sync.convert_wait(|semaphore| match waits.get_mut(&semaphore) {
                    None => {
                        let (signal, wait) = new_semaphore();
                        let old = signals.insert(semaphore, Some(signal));
                        assert!(old.is_none());
                        wait
                    }
                    Some(wait) => wait.take().unwrap(),
                });
                sync
            } else {
                SyncData::new()
            };
            new_queue.add_submission_checked(submission.set_sync(sync));
        }
        result.set_queue(new_queue);
    }

    debug_assert!(sync.0.is_empty());
    debug_assert!(signals.values().all(|x| x.is_none()));
    debug_assert!(waits.values().all(|x| x.is_none()));

    result
}

// submit_order creates a consistent direction in which semaphores are generated, avoiding issues
// with deadlocks.
fn latest<R, S>(link: &Link<R>, schedule: &Schedule<S>) -> SubmissionId
where
    R: Resource,
{
    let (_, sid) = link
        .queues()
        .map(|(qid, queue)| {
            let sid = SubmissionId::new(qid, queue.last);
            (schedule[sid].submit_order(), sid)
        })
        .max_by_key(|&(submit_order, sid)| (submit_order, sid.queue().index()))
        .unwrap();
    sid
}

fn earliest<R, S>(link: &Link<R>, schedule: &Schedule<S>) -> SubmissionId
where
    R: Resource,
{
    let (_, sid) = link
        .queues()
        .map(|(qid, queue)| {
            let sid = SubmissionId::new(qid, queue.first);
            (schedule[sid].submit_order(), sid)
        })
        .min_by_key(|&(submit_order, sid)| (submit_order, sid.queue().index()))
        .unwrap();
    sid
}

fn generate_semaphore_pair<R: Resource>(
    sync: &mut SyncTemp,
    id: Id,
    link: &Link<R>,
    range: Range<SubmissionId>,
) {
    if range.start.queue() != range.end.queue() {
        let semaphore = Semaphore::new(id, range.clone());
        sync.get_sync(range.start)
            .signal
            .push(Signal::new(semaphore.clone()));
        sync.get_sync(range.end)
            .wait
            .push(Wait::new(semaphore, link.queue(range.end.queue()).stages));
    }
}

fn sync_chain<R, S>(id: Id, chain: &Chain<R>, schedule: &Schedule<S>, sync: &mut SyncTemp)
where
    R: Resource,
{
    let uid = id.into();

    let pairs = chain
        .links()
        .windows(2)
        .map(|pair| (&pair[0], &pair[1]))
        .chain(
            chain
                .links()
                .first()
                .and_then(|first| chain.links().last().map(move |last| (last, first))),
        );

    for (prev_link, link) in pairs {
        log::trace!("Sync {:#?}:{:#?}", prev_link.access(), link.access());
        if prev_link.family() == link.family() {
            // Prefer to generate barriers on the acquire side, if possible.
            if prev_link.access().exclusive() && !link.access().exclusive() {
                let signal_sid = latest(prev_link, schedule);

                // Generate barrier in prev link's last submission.
                sync.get_sync(signal_sid)
                    .release
                    .pick::<R>()
                    .insert(id, Barrier::new(prev_link.state()..link.state()));

                // Generate semaphores between queues in the previous link and the current one.
                for (queue_id, queue) in link.queues() {
                    let head = SubmissionId::new(queue_id, queue.first);
                    generate_semaphore_pair(sync, uid, link, signal_sid..head);
                }
            } else {
                let wait_sid = earliest(link, schedule);

                // Generate semaphores between queues in the previous link and the current one.
                for (queue_id, queue) in prev_link.queues() {
                    let tail = SubmissionId::new(queue_id, queue.last);
                    generate_semaphore_pair(sync, uid, link, tail..wait_sid);
                }

                // Generate barrier in next link's first submission.
                sync.get_sync(wait_sid)
                    .acquire
                    .pick()
                    .insert(id, Barrier::new(prev_link.state()..link.state()));

                if !link.access().exclusive() {
                    unimplemented!("This case is unimplemented");
                }
            }
        } else {
            let signal_sid = latest(prev_link, schedule);
            let wait_sid = earliest(link, schedule);

            if !prev_link.access().exclusive() {
                unimplemented!("This case is unimplemented");
            }

            // Generate a semaphore between the signal and wait sides of the transfer.
            generate_semaphore_pair(sync, uid, link, signal_sid..wait_sid);

            // Generate barriers to transfer the resource to another family.
            sync.get_sync(signal_sid).release.pick::<R>().insert(
                id,
                Barrier::release(
                    signal_sid.family()..wait_sid.family(),
                    (prev_link.access(), prev_link.layout())..,
                    ..link.layout(),
                ),
            );
            sync.get_sync(wait_sid).acquire.pick::<R>().insert(
                id,
                Barrier::acquire(
                    signal_sid.family()..wait_sid.family(),
                    prev_link.layout()..,
                    ..(link.access(), link.layout()),
                ),
            );

            if !link.access().exclusive() {
                unimplemented!("This case is unimplemented");
            }
        }
    }
}

fn optimize_submission(
    sid: SubmissionId,
    found: &mut HashMap<QueueId, usize>,
    sync: &mut SyncTemp,
) {
    let mut to_remove = Vec::new();
    if let Some(sync_data) = sync.0.get_mut(&sid) {
        sync_data
            .wait
            .sort_unstable_by_key(|wait| (wait.stage(), wait.semaphore().points.end.index()));
        sync_data.wait.retain(|wait| {
            let start = wait.semaphore().points.start;
            if let Some(synched_to) = found.get_mut(&start.queue()) {
                if *synched_to >= start.index() {
                    to_remove.push(wait.semaphore().clone());
                    return false;
                } else {
                    *synched_to = start.index();
                    return true;
                }
            }
            found.insert(start.queue(), start.index());
            true
        });
    } else {
        return;
    }

    for semaphore in to_remove.drain(..) {
        // Delete signal as well.
        let ref mut signal = sync.0.get_mut(&semaphore.points.start).unwrap().signal;
        let index = signal
            .iter()
            .position(|signal| signal.0 == semaphore)
            .unwrap();
        signal.swap_remove(index);
    }
}

fn optimize<S>(schedule: &Schedule<S>, sync: &mut SyncTemp) {
    for queue in schedule.iter().flat_map(|family| family.iter()) {
        let mut found = HashMap::default();
        for submission in queue.iter() {
            optimize_submission(submission.id(), &mut found, sync);
        }
    }
}