[RUNTIME] Replace random number with UUID #3544
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jlebar
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Apr 3, 2024
njhill
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May 28, 2024
… TP case (#34) We are seeing Mixtral pods with TP>1 failing with errors like: ``` FileNotFoundError: [Errno 2] No such file or directory: '/home/vllm/.triton/cache/c926ad2ef143810ed738a313c473c7b2/fused_moe_kernel.cubin.tmp.pid_72_945989' ``` It seems like there is some conflict in the Triton cache directories when using multi-processing. This has actually been [fixed](triton-lang/triton#3544) upstream in Triton, but the fix hasn't made it into Triton v2.3.0 which is what vLLM is currently using. This change essentially applies same fix that has made it into Triton main branch inside our container. --------- Signed-off-by: Thomas Parnell <tpa@zurich.ibm.com>
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ThomasRaoux
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Jul 10, 2024
…4295) # Summary there've been multiple issues discussing around the `FileNotFoundError` on compilation when `CompiledKernel` is trying to read from the listed ASM files. #2688 #4002 vllm-project/vllm#6103 etc. and there have been some attempts to address it such as #3544 . This PR attempts to explain the root cause and suggest a fix. # Why When a kernel is being compiled, triton first writes IRs to triton cache dir ([ref](https://github.com/triton-lang/triton/blob/78091647fccb6825ed9956ff7c0300859856d261/python/triton/compiler/compiler.py#L289)). Inside of the write operation, the process first writes it to a temp file unique to the current process (plus a uuid to distinguish between multiple processes with same PID on different hosts sharing the same underlying FS) ([ref](https://github.com/triton-lang/triton/blob/c14b033cd979d5c39e5fdb3847c022fa5d71a0c1/python/triton/runtime/cache.py#L124-L130)) and then atomically `os.replace` it to the final file name. Afterwards the `CompiledKernel` lists all the IRs and reads them ([ref](https://github.com/triton-lang/triton/blob/78091647fccb6825ed9956ff7c0300859856d261/python/triton/compiler/compiler.py#L362-L367)). On multiprocess set up this may however result in a race condition. Let's focus on a case where there's one host with 2 processes on it.  At the time when `pid 1` lists ASMs, the dir may contain temp files generated from another process `pid 2`. However at the time when `pid 1` proceeds to read bytes from the listed files, `pid2` may have already `os.replace`ed its temp files, so `pid 1` will encounter `FileNotFoundError` when trying to read the temp file generated by `pid 2`. IBM/vllm#35 (comment) also believes this is the root cause. # How There're multiple potential solutions towards this, as mentioned in IBM/vllm#35 (comment) as well: - let each process write to a private temp dir instead so `glob` won't bother taking the temp stuff into consideration - or, exclude `tmp.pid_*` from `glob` This PR tries to go with the 1st approach to avoid adding an assumption on the tmp file pattern (which is only used in `runtime/cache.py`) in `compiler/compiler.py` but is open to any suggestion. Thanks! Complete the following tasks before sending your PR, and replace `[ ]` with `[x]` to indicate you have done them. - [x] I am not making a trivial change, such as fixing a typo in a comment. - [x] I have written a PR description following these [rules](https://cbea.ms/git-commit/#why-not-how). - [x] I have run `pre-commit run --from-ref origin/main --to-ref HEAD`. - Select one of the following. - [ ] I have added tests. - `/test` for `lit` tests - `/unittest` for C++ tests - `/python/test` for end-to-end tests - [x] This PR does not need a test because `not applicable`. - Select one of the following. - [x] I have not added any `lit` tests. - [ ] The `lit` tests I have added follow these [best practices](https://mlir.llvm.org/getting_started/TestingGuide/#filecheck-best-practices), including the "tests should be minimal" section. (Usually running Python code and using the instructions it generates is not minimal.)
bertmaher
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Dec 10, 2024
…riton-lang#4295) # Summary there've been multiple issues discussing around the `FileNotFoundError` on compilation when `CompiledKernel` is trying to read from the listed ASM files. triton-lang#2688 triton-lang#4002 vllm-project/vllm#6103 etc. and there have been some attempts to address it such as triton-lang#3544 . This PR attempts to explain the root cause and suggest a fix. # Why When a kernel is being compiled, triton first writes IRs to triton cache dir ([ref](https://github.com/triton-lang/triton/blob/78091647fccb6825ed9956ff7c0300859856d261/python/triton/compiler/compiler.py#L289)). Inside of the write operation, the process first writes it to a temp file unique to the current process (plus a uuid to distinguish between multiple processes with same PID on different hosts sharing the same underlying FS) ([ref](https://github.com/triton-lang/triton/blob/c14b033cd979d5c39e5fdb3847c022fa5d71a0c1/python/triton/runtime/cache.py#L124-L130)) and then atomically `os.replace` it to the final file name. Afterwards the `CompiledKernel` lists all the IRs and reads them ([ref](https://github.com/triton-lang/triton/blob/78091647fccb6825ed9956ff7c0300859856d261/python/triton/compiler/compiler.py#L362-L367)). On multiprocess set up this may however result in a race condition. Let's focus on a case where there's one host with 2 processes on it.  At the time when `pid 1` lists ASMs, the dir may contain temp files generated from another process `pid 2`. However at the time when `pid 1` proceeds to read bytes from the listed files, `pid2` may have already `os.replace`ed its temp files, so `pid 1` will encounter `FileNotFoundError` when trying to read the temp file generated by `pid 2`. IBM/vllm#35 (comment) also believes this is the root cause. # How There're multiple potential solutions towards this, as mentioned in IBM/vllm#35 (comment) as well: - let each process write to a private temp dir instead so `glob` won't bother taking the temp stuff into consideration - or, exclude `tmp.pid_*` from `glob` This PR tries to go with the 1st approach to avoid adding an assumption on the tmp file pattern (which is only used in `runtime/cache.py`) in `compiler/compiler.py` but is open to any suggestion. Thanks! Complete the following tasks before sending your PR, and replace `[ ]` with `[x]` to indicate you have done them. - [x] I am not making a trivial change, such as fixing a typo in a comment. - [x] I have written a PR description following these [rules](https://cbea.ms/git-commit/#why-not-how). - [x] I have run `pre-commit run --from-ref origin/main --to-ref HEAD`. - Select one of the following. - [ ] I have added tests. - `/test` for `lit` tests - `/unittest` for C++ tests - `/python/test` for end-to-end tests - [x] This PR does not need a test because `not applicable`. - Select one of the following. - [x] I have not added any `lit` tests. - [ ] The `lit` tests I have added follow these [best practices](https://mlir.llvm.org/getting_started/TestingGuide/#filecheck-best-practices), including the "tests should be minimal" section. (Usually running Python code and using the instructions it generates is not minimal.)
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On a distributed setting, processes from different nodes may have the same PID. If the seed for
randomis also set, the random number is also the same, which may finally lead to collision (actually happened on my cluster).Changing the random number to
uuidavoids such collision.