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comparison: js/src/builtin/ParallelUtilities.js
js/src/builtin/ParallelUtilities.js
- branch
- TOR_BUG_3246
- changeset 7
- 129ffea94266
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| -1:000000000000 | 0:6a1de34947c4 |
|---|---|
| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 // Shared utility functions for and macros parallel operations in `Array.js` | |
| 6 // and `TypedObject.js`. | |
| 7 | |
| 8 #ifdef ENABLE_PARALLEL_JS | |
| 9 | |
| 10 /* The mode asserts options object. */ | |
| 11 #define TRY_PARALLEL(MODE) \ | |
| 12 ((!MODE || MODE.mode !== "seq")) | |
| 13 #define ASSERT_SEQUENTIAL_IS_OK(MODE) \ | |
| 14 do { if (MODE) AssertSequentialIsOK(MODE) } while(false) | |
| 15 | |
| 16 /** | |
| 17 * The ParallelSpew intrinsic is only defined in debug mode, so define a dummy | |
| 18 * if debug is not on. | |
| 19 */ | |
| 20 #ifndef DEBUG | |
| 21 #define ParallelSpew(args) | |
| 22 #endif | |
| 23 | |
| 24 #define MAX_SLICE_SHIFT 6 | |
| 25 #define MAX_SLICE_SIZE 64 | |
| 26 #define MAX_SLICES_PER_WORKER 8 | |
| 27 | |
| 28 /** | |
| 29 * Macros to help compute the start and end indices of slices based on id. Use | |
| 30 * with the object returned by ComputeSliceInfo. | |
| 31 */ | |
| 32 #define SLICE_START_INDEX(shift, id) \ | |
| 33 (id << shift) | |
| 34 #define SLICE_END_INDEX(shift, start, length) \ | |
| 35 std_Math_min(start + (1 << shift), length) | |
| 36 | |
| 37 /** | |
| 38 * ForkJoinGetSlice acts as identity when we are not in a parallel section, so | |
| 39 * pass in the next sequential value when we are in sequential mode. The | |
| 40 * reason for this odd API is because intrinsics *need* to be called during | |
| 41 * ForkJoin's warmup to fill the TI info. | |
| 42 */ | |
| 43 #define GET_SLICE(sliceStart, sliceEnd, id) \ | |
| 44 ((id = ForkJoinGetSlice((InParallelSection() ? -1 : sliceStart++) | 0)) < sliceEnd) | |
| 45 | |
| 46 /** | |
| 47 * Determine the number and size of slices. The info object has the following | |
| 48 * properties: | |
| 49 * | |
| 50 * - shift: amount to shift by to compute indices | |
| 51 * - count: number of slices | |
| 52 */ | |
| 53 function ComputeSlicesInfo(length) { | |
| 54 var count = length >>> MAX_SLICE_SHIFT; | |
| 55 var numWorkers = ForkJoinNumWorkers(); | |
| 56 if (count < numWorkers) | |
| 57 count = numWorkers; | |
| 58 else if (count >= numWorkers * MAX_SLICES_PER_WORKER) | |
| 59 count = numWorkers * MAX_SLICES_PER_WORKER; | |
| 60 | |
| 61 // Round the slice size to be a power of 2. | |
| 62 var shift = std_Math_max(std_Math_log2(length / count) | 0, 1); | |
| 63 | |
| 64 // Recompute count with the rounded size. | |
| 65 count = length >>> shift; | |
| 66 if (count << shift !== length) | |
| 67 count += 1; | |
| 68 | |
| 69 return { shift: shift, count: count }; | |
| 70 } | |
| 71 | |
| 72 #endif // ENABLE_PARALLEL_JS |
