1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/builtin/ParallelUtilities.js Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,72 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +// Shared utility functions for and macros parallel operations in `Array.js`
1.9 +// and `TypedObject.js`.
1.10 +
1.11 +#ifdef ENABLE_PARALLEL_JS
1.12 +
1.13 +/* The mode asserts options object. */
1.14 +#define TRY_PARALLEL(MODE) \
1.15 + ((!MODE || MODE.mode !== "seq"))
1.16 +#define ASSERT_SEQUENTIAL_IS_OK(MODE) \
1.17 + do { if (MODE) AssertSequentialIsOK(MODE) } while(false)
1.18 +
1.19 +/**
1.20 + * The ParallelSpew intrinsic is only defined in debug mode, so define a dummy
1.21 + * if debug is not on.
1.22 + */
1.23 +#ifndef DEBUG
1.24 +#define ParallelSpew(args)
1.25 +#endif
1.26 +
1.27 +#define MAX_SLICE_SHIFT 6
1.28 +#define MAX_SLICE_SIZE 64
1.29 +#define MAX_SLICES_PER_WORKER 8
1.30 +
1.31 +/**
1.32 + * Macros to help compute the start and end indices of slices based on id. Use
1.33 + * with the object returned by ComputeSliceInfo.
1.34 + */
1.35 +#define SLICE_START_INDEX(shift, id) \
1.36 + (id << shift)
1.37 +#define SLICE_END_INDEX(shift, start, length) \
1.38 + std_Math_min(start + (1 << shift), length)
1.39 +
1.40 +/**
1.41 + * ForkJoinGetSlice acts as identity when we are not in a parallel section, so
1.42 + * pass in the next sequential value when we are in sequential mode. The
1.43 + * reason for this odd API is because intrinsics *need* to be called during
1.44 + * ForkJoin's warmup to fill the TI info.
1.45 + */
1.46 +#define GET_SLICE(sliceStart, sliceEnd, id) \
1.47 + ((id = ForkJoinGetSlice((InParallelSection() ? -1 : sliceStart++) | 0)) < sliceEnd)
1.48 +
1.49 +/**
1.50 + * Determine the number and size of slices. The info object has the following
1.51 + * properties:
1.52 + *
1.53 + * - shift: amount to shift by to compute indices
1.54 + * - count: number of slices
1.55 + */
1.56 +function ComputeSlicesInfo(length) {
1.57 + var count = length >>> MAX_SLICE_SHIFT;
1.58 + var numWorkers = ForkJoinNumWorkers();
1.59 + if (count < numWorkers)
1.60 + count = numWorkers;
1.61 + else if (count >= numWorkers * MAX_SLICES_PER_WORKER)
1.62 + count = numWorkers * MAX_SLICES_PER_WORKER;
1.63 +
1.64 + // Round the slice size to be a power of 2.
1.65 + var shift = std_Math_max(std_Math_log2(length / count) | 0, 1);
1.66 +
1.67 + // Recompute count with the rounded size.
1.68 + count = length >>> shift;
1.69 + if (count << shift !== length)
1.70 + count += 1;
1.71 +
1.72 + return { shift: shift, count: count };
1.73 +}
1.74 +
1.75 +#endif // ENABLE_PARALLEL_JS
