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/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can
* be found in the LICENSE file.
*
*/
//
// FIXME -- a pre-allocation step could load the path header quads and
// total up the number of blocks in the workgroup or subgroup
// minimizing the number of later atomics adds.
//
#include "device_cl_12_gen9.h"
#include "block_pool_cl.h"
#include "atomic_cl.h"
#include "block.h"
#include "path.h"
#include "common.h"
//
//
//
#define SKC_PATHS_RECLAIM_SUBGROUP_SIZE_MASK (SKC_PATHS_RECLAIM_SUBGROUP_SIZE - 1)
#define SKC_PATHS_RECLAIM_SUBGROUP_ELEMS (SKC_PATHS_RECLAIM_SUBGROUP_SIZE * SKC_PATHS_RECLAIM_LOCAL_ELEMS)
#define SKC_PATHS_RECLAIM_X (SKC_DEVICE_BLOCK_WORDS / SKC_PATHS_RECLAIM_SUBGROUP_ELEMS)
//
//
//
#if ( SKC_PATHS_RECLAIM_X == 1 )
#define SKC_PATHS_RECLAIM_BLOCK_EXPAND() SKC_EXPAND_1()
#define SKC_PATHS_RECLAIM_BLOCK_EXPAND_I_LAST 0
#elif ( SKC_PATHS_RECLAIM_X == 2 )
#define SKC_PATHS_RECLAIM_BLOCK_EXPAND() SKC_EXPAND_2()
#define SKC_PATHS_RECLAIM_BLOCK_EXPAND_I_LAST 1
#elif ( SKC_PATHS_RECLAIM_X == 4 )
#define SKC_PATHS_RECLAIM_BLOCK_EXPAND() SKC_EXPAND_4()
#define SKC_PATHS_RECLAIM_BLOCK_EXPAND_I_LAST 3
#elif ( SKC_PATHS_RECLAIM_X == 8 )
#define SKC_PATHS_RECLAIM_BLOCK_EXPAND() SKC_EXPAND_8()
#define SKC_PATHS_RECLAIM_BLOCK_EXPAND_I_LAST 7
#elif ( SKC_PATHS_RECLAIM_X == 16)
#define SKC_PATHS_RECLAIM_BLOCK_EXPAND() SKC_EXPAND_16()
#define SKC_PATHS_RECLAIM_BLOCK_EXPAND_I_LAST 15
#else
#error "MISSING SKC_PATHS_RECLAIM_X"
#endif
//
// FIXME -- slate these for replacement
//
#define SKC_BROADCAST(E,S,I) \
sub_group_broadcast(E,S - I * SKC_PATHS_RECLAIM_SUBGROUP_SIZE)
#define SKC_BROADCAST_LAST_HELPER(E,I) \
sub_group_broadcast(E,SKC_PATHS_RECLAIM_SUBGROUP_SIZE - 1)
#define SKC_BROADCAST_LAST(E,I) \
SKC_BROADCAST_LAST_HELPER(E,I)
//
// COMPILE-TIME PREDICATES
//
#define SKC_PATHS_RECLAIM_ELEM_GTE(X,I) \
SKC_GTE_MACRO(X,(I+1) * SKC_PATHS_RECLAIM_SUBGROUP_SIZE)
#define SKC_PATHS_RECLAIM_ELEM_IN_RANGE(X,I) \
(skc_bool)SKC_GTE_MACRO(X, I * SKC_PATHS_RECLAIM_SUBGROUP_SIZE) && \
(skc_bool)SKC_LT_MACRO(X,(I+1) * SKC_PATHS_RECLAIM_SUBGROUP_SIZE)
#define SKC_PATHS_RECLAIM_ENTIRELY_HEADER(I) \
SKC_PATHS_RECLAIM_ELEM_GTE(SKC_PATH_HEAD_WORDS,I)
#define SKC_PATHS_RECLAIM_PARTIALLY_HEADER(I) \
SKC_PATHS_RECLAIM_ELEM_IN_RANGE(SKC_PATH_HEAD_WORDS,I)
//
// RUN-TIME PREDICATES
//
#define SKC_PATHS_RECLAIM_IS_HEADER(I) \
(get_sub_group_local_id() + I * SKC_PATHS_RECLAIM_SUBGROUP_SIZE < SKC_PATH_HEAD_WORDS)
//
// FIXME -- THIS BITFIELD SCAN APPROACH CAN BE PARAMETERIZED FOR ALL
// POSSIBLE PRACTICAL POWER-OF-TWO SUBGROUP AND SUBBLOCKS-PER-BLOCK
// COMBOS (NOT NECESSARILY POW2)
//
// FOR WIDER SUBGROUPS WITH BIG BLOCKS, WE WILL WANT TO USE A VECTOR
// UINT TYPE INSTEAD OF A ULONG.
//
#define SKC_PATHS_RECLAIM_PACKED_COUNT_BITS SKC_PATHS_RECLAIM_SUBGROUP_SIZE_LOG2
#define SKC_PATHS_RECLAIM_PACKED_COUNT_DECLARE skc_uint
//
//
//
#define SKC_PATHS_RECLAIM_PACKED_COUNT_MASK SKC_BITS_TO_MASK(SKC_PATHS_RECLAIM_PACKED_COUNT_BITS)
#define SKC_PATHS_RECLAIM_PACKED_COUNT_IS_BLOCK(E,I) \
(((E) & SKC_DEVICE_SUBBLOCKS_PER_BLOCK_MASK) \
? 0 : (1u << SKC_PATHS_RECLAIM_PACKED_COUNT_BITS * I))
#define SKC_PATHS_RECLAIM_PACKED_COUNT_SCAN_EXCLUSIVE_ADD(S,C) \
S = sub_group_scan_exclusive_add(C)
#define SKC_PATHS_RECLAIM_PACKED_COUNT_GET(C,I) \
(((C) >> (SKC_PATHS_RECLAIM_PACKED_COUNT_BITS * I)) & SKC_PATHS_RECLAIM_PACKED_COUNT_MASK)
//
//
//
struct skc_reclaim
{
skc_path_h aN[SKC_RECLAIM_ARRAY_SIZE];
};
__kernel
SKC_PATHS_RECLAIM_KERNEL_ATTRIBS
void
skc_kernel_paths_reclaim(__global skc_block_id_t * const bp_ids, // block pool ids ring
__global skc_uint * const bp_elems, // block pool blocks
__global skc_uint volatile * const bp_atomics, // read/write atomics
skc_uint const bp_mask, // pow2 modulo mask for block pool ring
__global skc_block_id_t const * const map, // path host-to-device map
struct skc_reclaim const reclaim) // array of host path ids
{
#if (__OPENCL_VERSION__ < 200)
skc_uint const reclaim_stride = get_num_sub_groups();
#else
skc_uint const reclaim_stride = get_enqueued_num_sub_groups(); // 2.0 supports non-uniform workgroups
#endif
skc_uint reclaim_idx = get_group_id(0) * reclaim_stride + get_sub_group_id();
#if 0
//
// NOTE -- FOR NOW, THIS KERNEL ALWAYS LAUNCHES FIXED SIZE GRIDS BUT
// WE MIGHT WANT TO HAVE THE GRID LIMIT ITSELF TO A FRACTIONAL
// MULTIPROCESSOR IN ORDER TO MINIMIZE THE IMPACT OF A LARGE
// RECLAMATION JOB ON THE REST OF THE PIPELINE.
//
for (; reclaim_idx < SKC_RECLAIM_ARRAY_SIZE; reclaim_idx+=reclaim_stride)
#endif
{
// get host path id
skc_path_h const path = reclaim.aN[reclaim_idx];
// get the path header block from the map
skc_block_id_t id = map[path];
//
// blindly load all of the head elements into registers
//
skc_uint const head_idx = id * SKC_DEVICE_SUBBLOCK_WORDS + get_sub_group_local_id();
#undef SKC_EXPAND_X
#define SKC_EXPAND_X(I,S,C,P,R) \
skc_uint h##I = bp_elems[head_idx + I * SKC_PATHS_RECLAIM_SUBGROUP_SIZE];
SKC_PATHS_RECLAIM_BLOCK_EXPAND();
//
// pick out count.nodes and count.prims from the header
//
skc_uint count_blocks, count_nodes;
#undef SKC_EXPAND_X
#define SKC_EXPAND_X(I,S,C,P,R) \
if (SKC_PATHS_RECLAIM_ELEM_IN_RANGE(SKC_PATH_HEAD_OFFSET_BLOCKS,I)) { \
count_blocks = SKC_BROADCAST(h##I,SKC_PATH_HEAD_OFFSET_BLOCKS,I); \
} \
if (SKC_PATHS_RECLAIM_ELEM_IN_RANGE(SKC_PATH_HEAD_OFFSET_NODES,I)) { \
count_nodes = SKC_BROADCAST(h##I,SKC_PATH_HEAD_OFFSET_NODES,I); \
}
SKC_PATHS_RECLAIM_BLOCK_EXPAND();
#if 0
if (get_sub_group_local_id() == 0) {
printf("reclaim paths: %9u / %5u / %5u\n",path,count_blocks,count_nodes);
}
#endif
//
// acquire a span in the block pool ids ring for reclaimed ids
//
// FIXME count_blocks and atomic add can be done in same lane
//
skc_uint bp_ids_base = 0;
if (get_sub_group_local_id() == 0) {
bp_ids_base = SKC_ATOMIC_ADD_GLOBAL_RELAXED_SUBGROUP(bp_atomics+SKC_BP_ATOMIC_OFFSET_WRITES,count_blocks);
#if 0
printf("paths: bp_ids_base = %u\n",bp_ids_base);
#endif
}
bp_ids_base = sub_group_broadcast(bp_ids_base,0);
//
// shift away the tagged block id's tag
//
#undef SKC_EXPAND_X
#define SKC_EXPAND_X(I,S,C,P,R) \
if (!SKC_PATHS_RECLAIM_ENTIRELY_HEADER(I)) { \
h##I = h##I >> SKC_TAGGED_BLOCK_ID_BITS_TAG; \
}
SKC_PATHS_RECLAIM_BLOCK_EXPAND();
//
// swap current id with next
//
if (get_sub_group_local_id() == SKC_PATHS_RECLAIM_SUBGROUP_SIZE - 1)
{
skc_block_id_t const next = SKC_CONCAT(h,SKC_PATHS_RECLAIM_BLOCK_EXPAND_I_LAST);
SKC_CONCAT(h,SKC_PATHS_RECLAIM_BLOCK_EXPAND_I_LAST) = id;
id = next;
}
//
// - we'll skip subgroups that are entirely header
//
// - but we need to mark any header elements that partially fill
// a subgroup as invalid tagged block ids
//
#undef SKC_EXPAND_X
#define SKC_EXPAND_X(I,S,C,P,R) \
if (!SKC_PATHS_RECLAIM_ENTIRELY_HEADER(I)) { \
if (SKC_PATHS_RECLAIM_PARTIALLY_HEADER(I)) { \
if (SKC_PATHS_RECLAIM_IS_HEADER(I)) { \
h##I = SKC_TAGGED_BLOCK_ID_INVALID; \
} \
} \
}
SKC_PATHS_RECLAIM_BLOCK_EXPAND();
{
//
// count reclaimable blocks in each lane
//
SKC_PATHS_RECLAIM_PACKED_COUNT_DECLARE packed_count = ( 0 );
#undef SKC_EXPAND_X
#define SKC_EXPAND_X(I,S,C,P,R) \
if (!SKC_PATHS_RECLAIM_ENTIRELY_HEADER(I)) { \
packed_count |= SKC_PATHS_RECLAIM_PACKED_COUNT_IS_BLOCK(h##I,I); \
}
SKC_PATHS_RECLAIM_BLOCK_EXPAND();
//
// scan to find index of each block
//
SKC_PATHS_RECLAIM_PACKED_COUNT_DECLARE packed_index = ( 0 );
SKC_PATHS_RECLAIM_PACKED_COUNT_SCAN_EXCLUSIVE_ADD(packed_index,packed_count);
//
// store blocks back to ring
//
#undef SKC_EXPAND_X
#define SKC_EXPAND_X(I,S,C,P,R) \
if (!SKC_PATHS_RECLAIM_ENTIRELY_HEADER(I)) { \
skc_uint const index = SKC_PATHS_RECLAIM_PACKED_COUNT_GET(packed_index,I); \
skc_uint const count = SKC_PATHS_RECLAIM_PACKED_COUNT_GET(packed_count,I); \
skc_uint const bp_ids_idx = (bp_ids_base + index) & bp_mask; \
if (count > 0) { \
bp_ids[bp_ids_idx] = h##I; \
} \
skc_uint const total = index + count; \
bp_ids_base += sub_group_broadcast(total,SKC_PATHS_RECLAIM_SUBGROUP_SIZE-1); \
}
SKC_PATHS_RECLAIM_BLOCK_EXPAND();
// printf("P %7u ! %u\n",bp_ids_idx,h##I);
}
//
// we're done if it was just the header
//
if (count_nodes == 0)
return;
//
// otherwise, walk the nodes
//
do {
// id of next block is in last lane
id = sub_group_broadcast(id,SKC_PATHS_RECLAIM_SUBGROUP_SIZE-1);
// get index of each element
skc_uint const node_idx = id * SKC_DEVICE_SUBBLOCK_WORDS + get_sub_group_local_id();
//
// blindly load all of the node elements into registers
//
#undef SKC_EXPAND_X
#define SKC_EXPAND_X(I,S,C,P,R) \
skc_uint n##I = bp_elems[node_idx + I * SKC_PATHS_RECLAIM_SUBGROUP_SIZE];
SKC_PATHS_RECLAIM_BLOCK_EXPAND();
//
// shift away the tagged block id's tag
//
#undef SKC_EXPAND_X
#define SKC_EXPAND_X(I,S,C,P,R) \
n##I = n##I >> SKC_TAGGED_BLOCK_ID_BITS_TAG;
SKC_PATHS_RECLAIM_BLOCK_EXPAND();
//
// swap current id with next
//
if (get_sub_group_local_id() == SKC_PATHS_RECLAIM_SUBGROUP_SIZE - 1)
{
skc_block_id_t const next = SKC_CONCAT(n,SKC_PATHS_RECLAIM_BLOCK_EXPAND_I_LAST);
SKC_CONCAT(n,SKC_PATHS_RECLAIM_BLOCK_EXPAND_I_LAST) = id;
id = next;
}
//
// count reclaimable blocks in each lane
//
SKC_PATHS_RECLAIM_PACKED_COUNT_DECLARE packed_count = ( 0 );
#undef SKC_EXPAND_X
#define SKC_EXPAND_X(I,S,C,P,R) \
packed_count |= SKC_PATHS_RECLAIM_PACKED_COUNT_IS_BLOCK(n##I,I);
SKC_PATHS_RECLAIM_BLOCK_EXPAND();
//
// scan to find index of each block
//
SKC_PATHS_RECLAIM_PACKED_COUNT_DECLARE packed_index = ( 0 );
SKC_PATHS_RECLAIM_PACKED_COUNT_SCAN_EXCLUSIVE_ADD(packed_index,packed_count);
//
// store blocks back to ring
//
#undef SKC_EXPAND_X
#define SKC_EXPAND_X(I,S,C,P,R) { \
skc_uint const index = SKC_PATHS_RECLAIM_PACKED_COUNT_GET(packed_index,I); \
skc_uint const count = SKC_PATHS_RECLAIM_PACKED_COUNT_GET(packed_count,I); \
skc_uint const bp_ids_idx = (bp_ids_base + index) & bp_mask; \
if (count > 0) { \
bp_ids[bp_ids_idx] = n##I; \
} \
skc_uint const total = index + count; \
bp_ids_base += sub_group_broadcast(total,SKC_PATHS_RECLAIM_SUBGROUP_SIZE-1); \
}
SKC_PATHS_RECLAIM_BLOCK_EXPAND();
// printf("P %7u ! %u\n",bp_ids_idx,n##I);
// any more nodes?
} while (--count_nodes > 0);
}
}
//
//
//
|
