This adds queue operations as described in https://github.com/pytorch/pytorch/issues/150943.
This works by adding two new operations `queue_push` and `queue_pop`. The semantics are designed to be blocking with a timeout. Pushing will always succeed as the queue is infinite size. Popping will first call `wait` until the key is ready and then pop the value from the queue.
This implements queues for only: HashStore, TCPStore w/ libuv. FileStore and the legacy backends are not supported.
`wait` and `check` work for queue operations though queue_push will only wake up the first waiter rather than all of them.
This also has a few cleanups to error types/documentation in related code.
Example trace:
```
[I409 16:51:43.963833529 TCPStoreLibUvBackend.cpp:829] [c10d - trace] validate magic:1015412686 address:[localhost]:55816
[I409 16:51:43.963845838 TCPStoreLibUvBackend.cpp:842] [c10d - trace] ping nonce:2840795 address:[localhost]:55816
[I409 16:51:43.963902914 TCPStoreLibUvBackend.cpp:911] [c10d - trace] add key:init/ val:1 address:[localhost]:55816
[I409 16:51:43.963939389 TCPStoreLibUvBackend.cpp:977] [c10d - trace] wait key_count:1 keys[0]:init/ address:[localhost]:55816
[I409 16:51:43.963974842 TCPStoreLibUvBackend.cpp:893] [c10d - trace] get key:init/ address:[localhost]:55816
[I409 16:51:43.964071909 TCPStoreLibUvBackend.cpp:1121] [c10d - trace] queue_push key:/test_prefix/test_queue_support address:[localhost]:55816
[I409 16:51:43.964080221 TCPStoreLibUvBackend.cpp:940] [c10d - trace] check key_count:1 keys[0]:/test_prefix/foo address:[localhost]:55816
[I409 16:51:43.964108584 TCPStoreLibUvBackend.cpp:1121] [c10d - trace] queue_push key:/test_prefix/foo address:[localhost]:55816
[I409 16:51:43.964123207 TCPStoreLibUvBackend.cpp:1121] [c10d - trace] queue_push key:/test_prefix/foo address:[localhost]:55816
[I409 16:51:43.964128194 TCPStoreLibUvBackend.cpp:940] [c10d - trace] check key_count:1 keys[0]:/test_prefix/foo address:[localhost]:55816
[I409 16:51:43.964156347 TCPStoreLibUvBackend.cpp:977] [c10d - trace] wait key_count:1 keys[0]:/test_prefix/foo address:[localhost]:55816
[I409 16:51:43.964187493 TCPStoreLibUvBackend.cpp:977] [c10d - trace] wait key_count:1 keys[0]:/test_prefix/foo address:[localhost]:55816
[I409 16:51:43.964217709 TCPStoreLibUvBackend.cpp:1133] [c10d - trace] queue_pop key:/test_prefix/foo address:[localhost]:55816
[I409 16:51:43.964324300 TCPStoreLibUvBackend.cpp:977] [c10d - trace] wait key_count:1 keys[0]:/test_prefix/foo address:[localhost]:55816
[I409 16:51:43.964354495 TCPStoreLibUvBackend.cpp:1133] [c10d - trace] queue_pop key:/test_prefix/foo address:[localhost]:55816
[I409 16:51:43.964416299 TCPStoreLibUvBackend.cpp:940] [c10d - trace] check key_count:1 keys[0]:/test_prefix/foo address:[localhost]:55816
[I409 16:51:43.964458733 TCPStoreLibUvBackend.cpp:977] [c10d - trace] wait key_count:1 keys[0]:/test_prefix/non_existant address:[localhost]:55816
[W409 16:51:43.974516585 socket.cpp:460] [c10d] waitForInput: poll for socket SocketImpl(fd=75, addr=[localhost]:55816, remote=[localhost]:46641) returned 0, likely a timeout
[W409 16:51:43.974559169 socket.cpp:485] [c10d] waitForInput: socket SocketImpl(fd=75, addr=[localhost]:55816, remote=[localhost]:46641) timed out after 10ms
[I409 16:51:43.974600451 TCPStoreLibUvBackend.cpp:1101] [c10d - trace] cancel_wait address:[localhost]:55816
```
Test plan:
```
$ pytest test/distributed/test_store.py -k queue -v -s
test/distributed/test_store.py::FileStoreTest::test_queues SKIPPED [0.4351s] (Store does not support queues)
test/distributed/test_store.py::HashStoreTest::test_queues PASSED [0.0009s]
test/distributed/test_store.py::PrefixFileStoreTest::test_queues SKIPPED [0.0006s] (Store does not support queues)
test/distributed/test_store.py::TCPStoreTest::test_queues SKIPPED [0.0012s] (Store does not support queues)
test/distributed/test_store.py::LibUvTCPStoreTest::test_queues PASSED [0.0014s]
test/distributed/test_store.py::PrefixTCPStoreTest::test_queues PASSED [0.0014s]
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/150969
Approved by: https://github.com/XilunWu, https://github.com/fduwjj
While fixing the memory leak in https://github.com/pytorch/pytorch/pull/145757, we accidentally close the socket for the case when nread == 0 and thought it is the case when connection is closed. This is not true. According to libuv doc: https://docs.libuv.org/en/v1.x/stream.html#c.uv_read_cb.
> nread might be 0, which does not indicate an error or EOF. This is equivalent to EAGAIN or EWOULDBLOCK under read(2).
We found this bug when debugging a broken pipe issue when users first call a set and then wait for all keys right afterwards on 128 ranks. This might also cause other broken pipe issues we have seen in the prod jobs recently.
Added a unit test to test this case.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/150987
Approved by: https://github.com/d4l3k, https://github.com/XilunWu
This supports `masterListenFd` which is required for full compatibility with the non-libuv TCPStore. The code was just missing a `uv_listen` call and now it works just fine.
This is required to migrate the last remaining uses of TCPStore off of the non-libuv backend.
Test plan:
```
pytest -v test/distributed/test_store.py -k test_take_over_listen_socket
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/150215
Approved by: https://github.com/fduwjj
This is a follow up to #147465 that changes most TORCH_CHECK calls in TCPStore and TCPStoreLibUvBackend to use typed exceptions instead of generic `TORCH_CHECK` calls which end up as RuntimeErrors in Python.
Test plan:
```
pytest test/distributed/test_store.py
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/147647
Approved by: https://github.com/fduwjj
This makes it easier to roll out `TORCHELASTIC_USE_AGENT_STORE` by opportunistically swallowing bind errors when the agent store is enabled and the port matches `MASTER_PORT`.
This should be very safe as if the store is somehow not up and the envs are set, the TCPStore client connections will fail to connect so we end up with a slightly different error message but success/failure behavior is identical.
This also pybinds `c10d::SocketError` into Python so we can assert on the error type in tests.
https://docs.google.com/document/d/1CzOn_N53AiFxWGgbyMWSnd2elCJd4lZ-ajPg2lzcxoM/edit?tab=t.0#heading=h.2j2f5dimrdau
Test plan:
```
pytest test/distributed/test_store.py
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/147465
Approved by: https://github.com/fduwjj
Summary:
Fix memory leak on shutdown when socket is closed.
We still need to free the buffer to make valgrind happy.
Test Plan:
Use `mtiavm`.
Repro steps provided by cristianlume.
on window 1:
```
vm ssh --vm=0 -- $(buck run @//neteng/ai/rdma_gen/mode/owl //neteng/ai/rdma_gen:rdma_gen --emit-shell) --rdma_mode=mtiav1 --num_ranks=2
```
on window 2:
```
vm ssh --vm=1 -- $(buck run @//neteng/ai/rdma_gen/mode/owl //neteng/ai/rdma_gen:rdma_gen --emit-shell) --rdma_mode=mtiav1 --num_ranks=2 --rank=1 --store_host=172.16.1.1
```
without the fix:
```
==8766==ERROR: LeakSanitizer: detected memory leaks
```
With fix, no leak
Differential Revision: D68566104
Pull Request resolved: https://github.com/pytorch/pytorch/pull/145507
Approved by: https://github.com/XilunWu, https://github.com/d4l3k
Summary:
This logs all operations when tracing log level is enabled for the `TCPStoreLibUvBackend`. This is very useful for debugging collective operations when issues occur as it logs all hosts and the keys that they're modifying. To minimize total data we only log the keys and not the values
This changes the C10D_* macros to be much more efficient -- previously we would always format the log string even if they would never be printed which is very wasteful for detailed tracing. This now gates them with an if statement to achieve the same behavior with no overhead
Test Plan:
```
TORCH_DISTRIBUTED_DEBUG=DETAIL torchrun --nnodes 1 --nproc_per_node 1 --no-python /bin/bash -c "echo foo"
```
```
I0919 09:26:52.352013 34271 TCPStore.cpp:285] [c10d - debug] The server has started on port = 29500.
I0919 09:26:52.352246 34271 socket.cpp:783] [c10d - debug] The client socket will attempt to connect to an IPv6 address of (127.0.0.1, 29500).
I0919 09:26:52.352241 36903 TCPStoreLibUvBackend.cpp:1173] [c10d - debug] Uv main loop running
I0919 09:26:52.352308 34271 socket.cpp:854] [c10d - trace] The client socket is attempting to connect to [localhost]:29500.
I0919 09:26:52.353633 34271 socket.cpp:945] [c10d] The client socket has connected to [localhost]:29500 on SocketImpl(fd=41, addr=[localhost]:45646, remote=[localhost]:29500).
I0919 09:26:52.354422 34271 TCPStore.cpp:321] [c10d - debug] TCP client connected to host 127.0.0.1:29500
I0919 09:26:52.354558 36903 TCPStoreLibUvBackend.cpp:774] [c10d - trace] validate magic:1015412686 address:[localhost]:45646
I0919 09:26:52.354638 36903 TCPStoreLibUvBackend.cpp:789] [c10d - trace] ping nonce:34271 address:[localhost]:45646
I0919 09:26:52.356122 36903 TCPStoreLibUvBackend.cpp:866] [c10d - trace] add key:init/ val:1 address:[localhost]:45646
I0919 09:26:52.356308 36903 TCPStoreLibUvBackend.cpp:930] [c10d - trace] wait key_count:1 address:[localhost]:45646
I0919 09:26:52.356410 36903 TCPStoreLibUvBackend.cpp:846] [c10d - trace] get key:init/ address:[localhost]:45646
I0919 09:26:52.358688 36903 TCPStoreLibUvBackend.cpp:808] [c10d - trace] set key:/none/torchelastic/role_info/0 address:[localhost]:45646
I0919 09:26:52.360177 36903 TCPStoreLibUvBackend.cpp:930] [c10d - trace] wait key_count:1 address:[localhost]:45646
I0919 09:26:52.360296 36903 TCPStoreLibUvBackend.cpp:1004] [c10d - trace] multi_get key_count:1 address:[localhost]:45646
I0919 09:26:52.362076 36903 TCPStoreLibUvBackend.cpp:1036] [c10d - trace] multi_set key_count:1 address:[localhost]:45646
I0919 09:26:52.364001 36903 TCPStoreLibUvBackend.cpp:930] [c10d - trace] wait key_count:1 address:[localhost]:45646
I0919 09:26:52.364091 36903 TCPStoreLibUvBackend.cpp:846] [c10d - trace] get key:/none/torchelastic/assigned_ranks/0 address:[localhost]:45646
```
Differential Revision: D62924454
Pull Request resolved: https://github.com/pytorch/pytorch/pull/136320
Approved by: https://github.com/c-p-i-o, https://github.com/XilunWu
While designing something else when TCPStore is needed. I spent some time digging into the codebase of TCPStore and found that the code is a little bit challenging to understand without proper documents. Although people from OSS community must be smarter than me, I still want to document my findings in the code so that devs and users can use them as a reference down the road.
Also for libuv, we need to make private variables with a "_", so it's a pure renaming of private variables such as `tcpServer`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/130496
Approved by: https://github.com/wconstab
Adds better error messages when a socket fails to bind in libuv.
New format:
```
The server socket has failed to bind. port: 1, useIpv6: 0, code: -13, name: EACCES, message: permission denied
```
Old format:
```
The server socket has failed to listen on any local network address. useIpv6: 0, code: -98, name: EADDRINUSE, message: address already in use
```
Test plan:
Added test in `test_store.py`
```
python test/distributed/test_store.py
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/130797
Approved by: https://github.com/kurman
This does a round trip request on socket connect -- this allows for detecting connection resets etc and retrying before the non-retryable application requests are sent.
This adds support for PING to both the libuv and legacy backend.
Example error:
```
[trainer85612|12]:W0701 13:41:43.421574 4776 TCPStore.cpp:182] [c10d] recvValue failed on SocketImpl(fd=24, ...): Connection reset by peer
[trainer85612|12]:Exception raised from recvBytes at /mnt/code/pytorch/torch/csrc/distributed/c10d/Utils.hpp:669 (most recent call first):
...
[trainer85612|12]:#9 c10d::TCPStore::incrementValueBy(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, long) from /packages/.../conda/lib/python3.10/site-packages/torch/lib/libtorch_cpu.so:84809637
[trainer85612|12]:#10 c10d::TCPStore::waitForWorkers() from /packages/.../conda/lib/python3.10/site-packages/torch/lib/libtorch_cpu.so:84812868
[trainer85612|12]:#11 c10d::TCPStore::TCPStore(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, c10d::TCPStoreOptions const&) from /packages/.../conda/lib/python3.10/site-packages/torch/lib/libtorch_cpu.so:84814775
```
Test plan:
```
python test/distributed/test_store.py -v
```
```
tristanr@devvm4382 ~/pytorch (d4l3k/tcpstore_ping)> python ~/pt_tests/tcpstore_large_test.py
starting pool
started 90000
started 30000
started 70000
started 20000
started 80000
started 60000
started 0
[W702 16:16:25.301681870 TCPStore.cpp:343] [c10d] Starting store with 100000 workers but somaxconn is 4096.This might cause instability during bootstrap, consider increasing it.
init 20000
set 20000
init 80000
set 80000
init 70000
set 70000
init 60000
set 60000
init 30000
set 30000
init 90000
set 90000
started 40000
init 40000
set 40000
started 50000
init 50000
set 50000
started 10000
init 10000
set 10000
init 0
set 0
run finished 617.2992351055145
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/129985
Approved by: https://github.com/rsdcastro, https://github.com/kurman
This adjusts the settings of the libuv backend to match the older TCPStore.
* DEFAULT_BACKLOG: setting this to -1 will enable using the host somaxconn value instead of a hardcoded 16k value. When going over this limit with `tcp_abort_on_overflow` set it results in connections being reset.
* TCP_NODELAY: Since TCPStore primarily sends small messages there's no benefit to using Nargle's algorithm and it may add additional latency for store operations.
Test plan:
```
python test/distributed/test_store.py -v -k LibUv
```
Benchmark script:
```
import time
import os
import torch.distributed as dist
rank = int(os.environ["RANK"])
store = dist.TCPStore(
host_name="<server>",
port=29500,
world_size=2,
is_master=(rank == 0),
use_libuv=True,
)
if rank == 1:
total_iters = 0
total_dur = 0
for iter in range(10):
iters = 500000
start = time.perf_counter()
for i in range(iters):
store.set(f"key_{i}", f"value_{i}")
dur = time.perf_counter() - start
print(f"{iter}. {iters} set, qps = {iters/dur}")
total_iters += iters
total_dur += dur
print(f"overall qps = {total_iters/total_dur}")
else:
print("sleeping")
time.sleep(1000000000)
```
Performance seems to be negligible difference between TCP_NODELAY and not for a single host
Pull Request resolved: https://github.com/pytorch/pytorch/pull/128739
Approved by: https://github.com/rsdcastro, https://github.com/kurman, https://github.com/c-p-i-o
This adds better logging of errors to the socket and TCPStore classes.
All socket operations should now include the local and remote addresses and we actually log errors from the TCPStoreBackend::run as well as TCPStoreBackendUV which were previously INFO messages and not actually logged.
It also overhauls test_wait in test_store.py as it had a race condition causing it to be flaky.
Test plan:
```
python test/distributed/test_store.py
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/128673
Approved by: https://github.com/c-p-i-o
**Summary**
This PR switches the default TCPStore server backend to a new implementation that utilizes [`libuv`](https://github.com/libuv/libuv) for significantly lower initialization time and better scalability:
<img width="714" alt="image" src="https://github.com/pytorch/pytorch/assets/12968408/18503011-da5d-4104-8ba9-abc456438b02">
We hope this improvement would benefit users from a much shorter startup time in large-scale jobs. Eventually, we hope to fully replace the old TCPStore backend implementation with the libuv one.
**What it changes**
This PR changes the underlying TCPStore server backend to `libuv` if users don't explicitly specify to use the old TCPStore server. This change is not supposed to cause any user notice except significant faster TCPStore startup for large-scale jobs.
One thing to note is, we do not support the initialization approach where user passes in a socket for libuv backend. We plan to support it as a next step but we choose to disable it before fully testing. If you are initializing TCPStore in this approach, you can see the next section to remain using the old TCPStore server.
**Fallback/Remain using the old TCPStore server**
For users who want to stay with the old TCPStore backend, there're 3 ways:
1. If user is directly instantiating TCPStore object, user can pass in argument `use_libuv=False` to use the old TCPStore server backend e.g. `store = torch.distributed.TCPStore(..., use_libuv=False)`.
2. Or, specify the TCPStore backend option in `init_method` when calling default ProcessGroup init, e.g. `torch.distributed.init_process_group(..., init_method="{YOUR_RENDEZVOUS_METHOD}://{YOUR_HOSTNAME}:{YOUR_PORT}?use_libuv=0")`
3. Or, user can set environment variable `USE_LIBUV` to `"0"` when launching.
These 3 approach are in order of precedence. That being said, if user specifies `use_libuv=0` in `init_method` and also sets environment var `USE_LIBUV="1"`, the former will take effect and the TCPStore backend instantiated will be the old one instead of the one using libuv.
**Operating Systems Compatibility**
From the CI signals, we believe the new implementation has the same behavior as the old TCPStore server on all supported platforms. If you notice any behavior discrepancy, please file an issue with `oncall: distributed` label.
**Test Plan**
`pytest test/distributed/test_store.py`
<img width="2548" alt="image" src="https://github.com/pytorch/pytorch/assets/12968408/dc0aebeb-6d5a-4daa-b98c-e56bd39aa588">
note: `TestMultiThreadedWait::test_wait` is a broken test that has been there for some time.
`test/distributed/elastic/utils/distributed_test.py`
<img width="2558" alt="image" src="https://github.com/pytorch/pytorch/assets/12968408/a6a3266d-b798-41c4-94d2-152056a034f6">
**TODO**
1. Update the doc at
- https://pytorch.org/docs/stable/distributed.html#distributed-key-value-store
- https://pytorch.org/docs/stable/distributed.html#tcp-initialization
2. Make torch elastic rendezvous to use libuv TCPStore as well. See `torch/distributed/elastic/rendezvous/c10d_rendezvous_backend.py` cc @mrshenli @pritamdamania87 @zhaojuanmao @satgera @gqchen @aazzolini @osalpekar @jiayisuse @H-Huang @kwen2501 @awgu @penguinwu @fegin @wanchaol @fduwjj @wz337 @tianyu-l @wconstab @yf225 @chauhang @d4l3k @kurman
3. Test if libuv backend is okay with initialization with socket. Change `LibUvTCPStoreTest::test_take_over_listen_socket`.
**Test Plan**
`pytest test/distributed/test_store.py`
<img width="2548" alt="image" src="https://github.com/pytorch/pytorch/assets/12968408/dc0aebeb-6d5a-4daa-b98c-e56bd39aa588">
note: `TestMultiThreadedWait::test_wait` is a broken test that has been there for some time.
`test/distributed/elastic/utils/distributed_test.py`
<img width="2558" alt="image" src="https://github.com/pytorch/pytorch/assets/12968408/a6a3266d-b798-41c4-94d2-152056a034f6">
Differential Revision: [D58259591](https://our.internmc.facebook.com/intern/diff/D58259591)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/127957
Approved by: https://github.com/kurman
ghstack dependencies: #127956
This PR fixes#106294.
Due to the lack of request validation mechanism, TCPStore in torch mistakenly treats nmap scan messages as valid query messages, which leads to DDP OOM. The simple solution enforces the very first query from a client is a validation query with a predefined magic number. If the validation fails, the server will terminate the connection.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107607
Approved by: https://github.com/cbalioglu, https://github.com/XilunWu
This PR fixes#106294.
Due to the lack of request validation mechanism, TCPStore in torch mistakenly treats nmap scan messages as valid query messages, which leads to DDP OOM. The simple solution enforces the very first query from a client is a validation query with a predefined magic number. If the validation fails, the server will terminate the connection.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107607
Approved by: https://github.com/cbalioglu, https://github.com/XilunWu
