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| author | Tim Hall <tim.hall@arm.com> | 2021-07-19 21:22:46 +0100 |
|---|---|---|
| committer | Tim Hall <tim.hall@arm.com> | 2021-07-19 21:22:46 +0100 |
| commit | daed1529848465aab221a30008f455f9fa03c8d4 (patch) | |
| tree | d98ec1b3138616a45651abee63c843a87c646c18 | |
| parent | a8c003909f6cfdbe7d71d40196920dd9e01c2467 (diff) | |
| download | ethos-u-vela-daed1529848465aab221a30008f455f9fa03c8d4.tar.gz | |
MLBEDSW-4812: Deep speech performance block config update
Deep speech was exhibiting poor performance in its first three
layers due to poor SHRAM utilisation.
- Given a choice between multiple identical-cost block configs,
the allocator was choosing the first one it encountered. This
commit biases the choice towards blocks with a larger IFM
fetch area to improve SHRAM utilisation.
Signed-off-by: Tim Hall <tim.hall@arm.com>
Change-Id: I2ff18a13444b8812cb451a606ff692bf290e7d20
| -rw-r--r-- | ethosu/vela/architecture_allocator.py | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/ethosu/vela/architecture_allocator.py b/ethosu/vela/architecture_allocator.py index 86410cfd..3c49eb13 100644 --- a/ethosu/vela/architecture_allocator.py +++ b/ethosu/vela/architecture_allocator.py @@ -263,6 +263,7 @@ def find_block_config( # Block WHC search, loops across the search space looking for best efficiency best_cost = math.inf + best_coverage = math.inf depth = max(arch.ofm_ublock.depth, min(search_space.depth, SplitDepth)) if depth < ofm_shape.depth: depth = round_up(depth, SplitDepth) @@ -309,12 +310,27 @@ def find_block_config( if ifm_shape.elements() < ifm_block.elements() * 2: relative_cost = relative_cost / 2 - if relative_cost < best_cost: - best_cost = relative_cost - config.layout = layout - config.bank_size = arch.shram_bank_size - config.ifm_block = ifm_block - config.ofm_block = Shape4D(1, height, width, depth) + # Choose based on relative minimum cost or larger IFM area (if equal cost) + if relative_cost <= best_cost: + choose_this = False + # Check IFM coverage only when it's equal best_cost and small OFM + if relative_cost == best_cost: + coverage_shape = Shape4D.min(ifm_shape, ifm_block) + coverage = ifm_shape.elements_wh() / coverage_shape.elements_wh() + # Small 4x4 IFM constraint found through analysis of networks + if coverage <= best_coverage and (height <= 4 and width <= 4): + best_coverage = coverage + choose_this = True + else: + best_coverage = math.inf + choose_this = True + + if choose_this: + best_cost = relative_cost + config.layout = layout + config.bank_size = arch.shram_bank_size + config.ifm_block = ifm_block + config.ofm_block = Shape4D(1, height, width, depth) else: wont_fit[(width, height)] = True |