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Use source hashing to generate consistent symbolic ids by bobrenjc93 · Pull Request #149665 · pytorch/pytorch · GitHub
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@bobrenjc93 bobrenjc93 commented Mar 20, 2025

Stack from ghstack (oldest at bottom):

This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run cache miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we cache miss with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions.

cc @ezyang @SherlockNoMad @EikanWang @jgong5 @wenzhe-nrv @voznesenskym @penguinwu @Guobing-Chen @XiaobingSuper @zhuhaozhe @blzheng @jiayisunx @ipiszy @chenyang78 @kadeng @muchulee8 @amjames @chauhang @aakhundov

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🧪 See artifacts and rendered test results at hud.pytorch.org/pr/149665

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@pytorch-bot pytorch-bot bot added ciflow/inductor release notes: fx release notes category labels Mar 20, 2025
bobrenjc93 added a commit that referenced this pull request Mar 20, 2025
ghstack-source-id: c52abed
Pull Request resolved: #149665
cc ezyang SherlockNoMad EikanWang jgong5 wenzhe-nrv

[ghstack-poisoned]
cc ezyang SherlockNoMad EikanWang jgong5 wenzhe-nrv voznesenskym penguinwu Guobing-Chen XiaobingSuper zhuhaozhe blzheng jiayisunx ipiszy chenyang78 kadeng muchulee8 amjames chauhang aakhundov

[ghstack-poisoned]
bobrenjc93 added a commit that referenced this pull request Mar 22, 2025
ghstack-source-id: 5a2daa1
Pull Request resolved: #149665
This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we look up with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions. 

[ghstack-poisoned]
This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we look up with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions. 

[ghstack-poisoned]
This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we look up with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions. 

[ghstack-poisoned]
This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we look up with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions. 

[ghstack-poisoned]
bobrenjc93 added a commit that referenced this pull request Mar 23, 2025
ghstack-source-id: 62a52af
Pull Request resolved: #149665
@bobrenjc93 bobrenjc93 changed the title Use hashing to generate consistent symbolic ids Use source hashing to generate consistent symbolic ids Mar 23, 2025
This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run cache miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we cache miss with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions. 

[ghstack-poisoned]
This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run cache miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we cache miss with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions. 

[ghstack-poisoned]
This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run cache miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we cache miss with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions. 

[ghstack-poisoned]
@bobrenjc93 bobrenjc93 added the keep-going Don't stop on first failure, keep running tests until the end label Mar 23, 2025
This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run cache miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we cache miss with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions. 

cc ezyang SherlockNoMad EikanWang jgong5 wenzhe-nrv voznesenskym penguinwu Guobing-Chen XiaobingSuper zhuhaozhe blzheng jiayisunx ipiszy chenyang78 kadeng muchulee8 amjames chauhang aakhundov

[ghstack-poisoned]
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Merge failed

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This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run cache miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we cache miss with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions. 

cc ezyang SherlockNoMad EikanWang jgong5 wenzhe-nrv voznesenskym penguinwu Guobing-Chen XiaobingSuper zhuhaozhe blzheng jiayisunx ipiszy chenyang78 kadeng muchulee8 amjames chauhang aakhundov

[ghstack-poisoned]
bobrenjc93 added a commit that referenced this pull request Mar 28, 2025
ghstack-source-id: 7e69b8f
Pull Request resolved: #149665
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laithsakka added a commit that referenced this pull request Apr 9, 2025
…n non args only "


PR 
#149665
added a change to the optimized add this causing an issue internally. 
In general make_optimized should be only called with non no args. 

cc ezyang SherlockNoMad EikanWang jgong5 wenzhe-nrv

[ghstack-poisoned]
laithsakka added a commit that referenced this pull request Apr 9, 2025
…n non args only "


PR 
#149665
added a change to the optimized add this causing an issue internally. 
In general make_optimized should be only called with valid new_args. 

cc ezyang SherlockNoMad EikanWang jgong5 wenzhe-nrv

[ghstack-poisoned]
laithsakka added a commit that referenced this pull request Apr 9, 2025
… called on non args only "


PR #149665 did a change to the optimized_add that is causing an issue internally. 
In general make_optimized should be only be called with valid new_args,  new_args can become None
when elements already exists also, we should break out of the loop in that case.

Note that I also only maintained the optimized summation when both lhs and rhs lengths are <=2.
This is ok because the optimization is based on the inductive property of adding one symbol at a time.
the [2]+[2] here is serving as base case ( i feel we can also remove it ) .

Note that keeping it for all sizes while correct, I am not sure if tis as efficient (we will do N log(n) insertions).
there is no current justification for that. 

cc ezyang SherlockNoMad EikanWang jgong5 wenzhe-nrv

[ghstack-poisoned]
pytorchmergebot pushed a commit that referenced this pull request Apr 10, 2025
…non args only (#150955)

PR #149665 did a change to the optimized_add that is causing an issue internally.
In general make_optimized should be only be called with valid new_args,  new_args can become None
when elements already exists also, we should break out of the loop in that case.

Note that I also only maintained the optimized summation when both lhs and rhs lengths are <=2.
This is ok because the optimization is based on the inductive property of adding one symbol at a time.
the [2]+[2] here is serving as base case ( i feel we can also remove it ) .

Note that keeping it for all sizes while correct, I am not sure if tis as efficient (we will do N log(n) insertions).
there is no current justification for that.

Pull Request resolved: #150955
Approved by: https://github.com/Mingming-Ding, https://github.com/atalman, https://github.com/bobrenjc93
timocafe pushed a commit to timocafe/pytorch that referenced this pull request Apr 16, 2025
…non args only (pytorch#150955)

PR pytorch#149665 did a change to the optimized_add that is causing an issue internally.
In general make_optimized should be only be called with valid new_args,  new_args can become None
when elements already exists also, we should break out of the loop in that case.

Note that I also only maintained the optimized summation when both lhs and rhs lengths are <=2.
This is ok because the optimization is based on the inductive property of adding one symbol at a time.
the [2]+[2] here is serving as base case ( i feel we can also remove it ) .

Note that keeping it for all sizes while correct, I am not sure if tis as efficient (we will do N log(n) insertions).
there is no current justification for that.

Pull Request resolved: pytorch#150955
Approved by: https://github.com/Mingming-Ding, https://github.com/atalman, https://github.com/bobrenjc93
amathewc pushed a commit to amathewc/pytorch that referenced this pull request Apr 17, 2025
This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run cache miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we cache miss with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions.

Pull Request resolved: pytorch#149665
Approved by: https://github.com/Mingming-Ding, https://github.com/laithsakka
amathewc pushed a commit to amathewc/pytorch that referenced this pull request Apr 17, 2025
This PR was inspired by internal models that were cache missing due to PGO. At a high level the problem looks as follows

Run 1, Invocation 1: We do static compile, save some example values in PGO/automatic dynamic

Run 1, Invocation 2: We detect varying inputs, do dynamic compile, get a dynamic graph and save to PGO. Crucially what we save to PGO is actually a superset of what is actually dynamic. If we notice an input was varying, we mark it as dynamic in PGO even if later on that value gets specialized. When a value gets specialized, we actually remove the symbol from the graph. This results in an interesting conundrum where although we are producing the same isomorphic graph, PGO makes the second run cache miss. Let's see how....

Run 2, Invocation 1: We fetch the PGO, over-mark things as dynamic, get a fx graph, look it up in the cache and... whoops! cache miss! This is because of the aforementioned behavior where the PGO profile will cause us to over-allocate symbols. In practice this means we end up saving a graph in cache with symbols x:s1, y:s3 and on second attempt we cache miss with x:s1, y:s6 where symbols s3,s4,s5 were all optimistically marked dynamic by PGO and subsequently specialized.

We solve this problem by hashing the source names. This ensures somewhat stable assignment. To prevent catastrophic symbol collisions, we use linear probing to ensure no collisions.

Pull Request resolved: pytorch#149665
Approved by: https://github.com/Mingming-Ding, https://github.com/laithsakka
amathewc pushed a commit to amathewc/pytorch that referenced this pull request Apr 17, 2025
…non args only (pytorch#150955)

PR pytorch#149665 did a change to the optimized_add that is causing an issue internally.
In general make_optimized should be only be called with valid new_args,  new_args can become None
when elements already exists also, we should break out of the loop in that case.

Note that I also only maintained the optimized summation when both lhs and rhs lengths are <=2.
This is ok because the optimization is based on the inductive property of adding one symbol at a time.
the [2]+[2] here is serving as base case ( i feel we can also remove it ) .

Note that keeping it for all sizes while correct, I am not sure if tis as efficient (we will do N log(n) insertions).
there is no current justification for that.

Pull Request resolved: pytorch#150955
Approved by: https://github.com/Mingming-Ding, https://github.com/atalman, https://github.com/bobrenjc93
@github-actions github-actions bot deleted the gh/bobrenjc93/303/head branch May 2, 2025 02:17
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