[GitHub] [tvm] mbaret commented on a change in pull request #9214: [TIR][USMP] Greedy memory planning algorithm

[GitBox <gi...@apache.org>]

mbaret commented on a change in pull request #9214:
URL: https://github.com/apache/tvm/pull/9214#discussion_r760238128



##########
File path: src/tir/usmp/algo/greedy.cc
##########
@@ -0,0 +1,231 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*!
+ * \file tir/analysis/usmp/algo/greedy.cc
+ * \brief This source contains greedy algorithms for planning
+ * memory for USMP. There are two algorithms present here :
+ * 1) greedy_by_size and 2) greedy_by_conflicts.
+ *
+ * greedy_by_size : this algorithm prioritizes placing the
+ * largest size buffer to the given pools. The BufferInfo objects
+ * are sorted based on the size and placed on each pool adhering
+ * to size_hint constraint.
+ *
+ * greedy_by_conflicts : this algorithm prioritizes placing the
+ * the most liveness conflicted buffer to the given pools. The
+ * BufferInfo objects are sorted based on the number of conflicts
+ * and placed on each pool adhering to size_hint constraint.
+ */
+
+#include <tvm/arith/analyzer.h>
+#include <tvm/runtime/device_api.h>
+#include <tvm/tir/builtin.h>
+#include <tvm/tir/function.h>
+#include <tvm/tir/stmt_functor.h>
+#include <tvm/tir/usmp/utils.h>
+
+namespace tvm {
+namespace tir {
+namespace usmp {
+namespace algo {
+
+/*!
+ * \brief This is the base class for Greedy Algorithms where the sorting
+ * is specialized in the extended classes based on the greedy criteria.
+ */
+class GreedyBase {
+ public:
+  GreedyBase() {}
+  /*!
+   * \brief This function should be implemented by the extended classes to sort the BufferInfo
+   * objects based on a criteria and then calling PostSortAllocation.
+   */
+  virtual Map<BufferInfo, PoolAllocation> PlanMemory(const Array<BufferInfo>& buffer_info_arr) = 0;
+
+ protected:
+  /*!
+   * \brief Rounds up the offset to satisfy the alignement requirement
+   */
+  size_t round_up_to_byte_alignment(const size_t& non_aligned_byte_offset,
+                                    const int& byte_alignment) {
+    return ((non_aligned_byte_offset + byte_alignment - 1) / byte_alignment) * byte_alignment;
+  }
+
+  /*!
+   * \brief A helper function check whether a offset is valid given the constraints
+   */
+  bool IsValidPlacement(const PoolInfo& candidate_pool, const size_t& next_offset,
+                        const size_t& size_bytes) {
+    if (candidate_pool->size_hint_bytes == -1) {
+      // this means pool is not bounded
+      return true;
+    }
+    auto pool_size = static_cast<size_t>(candidate_pool->size_hint_bytes->value);
+    auto max_address = next_offset + size_bytes;
+    if (max_address <= pool_size) {
+      return true;
+    }
+    return false;
+  }
+
+  /*!
+   * \brief Selects a pool for placement in the given set of ordered pool candidates
+   */
+  PoolInfo SelectPlacementPool(
+      const BufferInfo& buf_info,
+      const std::unordered_map<PoolInfo, size_t, ObjectPtrHash, ObjectPtrEqual>& pool_offsets) {
+    // Here the pool candidates are ordered when it is consumed by the algorithm.
+    // This could be from order the user has specified. However, schedulers are
+    // welcome to change the order for performance reasons.
+    for (const auto& pool_info : buf_info->pool_candidates) {
+      if (pool_offsets.count(pool_info)) {
+        return pool_info;
+      }
+    }
+    CHECK(false) << "TVM USMP Error: no candidate have been selected for " << buf_info;

Review comment:
       I think this needs to be more obvious because it'll be directly user-facing. Probably it needs to indicate that TVM has exceeded the pool memory limits and suggest to increase them if you want the compilation to pass. Let's not block the whole patch on this though, happy to take it in a follow-up.




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: commits-unsubscribe@tvm.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org