merrymercy commented on a change in pull request #6042:
URL: https://github.com/apache/incubator-tvm/pull/6042#discussion_r453785929
##########
File path: src/tir/transforms/unroll_loop.cc
##########
@@ -57,6 +58,9 @@ struct UnrollLoopConfigNode : public
tvm::AttrsNode<UnrollLoopConfigNode> {
TVM_ATTR_FIELD(explicit_unroll)
.describe("Whether to explicitly unroll the loop instead of setting a
pragma")
.set_default(true);
+ TVM_ATTR_FIELD(explicit_unroll_max_extent)
+ .describe("The maximum extent of a loop that can be unrolled
explicitly (-1 for infinite)")
+ .set_default(32);
Review comment:
I think 32 is a very safe value.
This value is just to avoid the llvm hanging issue, not for code
performance. 32 is enough to avoid almost all llvm issues. For the code
performance, the schedule developers should choose a reasonable unroll factor
by themself.
As a global configuration, this default value should be large enough to
avoid performance regression. And I do not think 16 is safe enough.
##########
File path: src/tir/transforms/unroll_loop.cc
##########
@@ -57,6 +58,9 @@ struct UnrollLoopConfigNode : public
tvm::AttrsNode<UnrollLoopConfigNode> {
TVM_ATTR_FIELD(explicit_unroll)
.describe("Whether to explicitly unroll the loop instead of setting a
pragma")
.set_default(true);
+ TVM_ATTR_FIELD(explicit_unroll_max_extent)
+ .describe("The maximum extent of a loop that can be unrolled
explicitly (-1 for infinite)")
+ .set_default(32);
Review comment:
I think 32 is a safe value.
This value is just to avoid the llvm hanging issue, not for code
performance. 32 is enough to avoid almost all llvm issues. For the code
performance, the schedule developers should choose a reasonable unroll factor
by themself.
As a global configuration, this default value should be large enough to
avoid performance regression. And I do not think 16 is safe enough.
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