# How to split runs (because of lack of multithreading) given a metric? **URL:** \ **Category:** W&B Help\ **Created:** [August 6, 2023, 12:27pm UTC](https://community.wandb.ai/t/how-to-split-runs-because-of-lack-of-multithreading-given-a-metric/4856 "2023-08-06T12:27:59Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![yann-berthelot](https://avatars.discourse-cdn.com/v4/letter/y/6f9a4e/32.png) [@yann-berthelot](https://community.wandb.ai/u/yann-berthelot)\ **Post date:** [August 6, 2023, 12:27pm UTC](https://community.wandb.ai/t/how-to-split-runs-because-of-lack-of-multithreading-given-a-metric/4856/1 "2023-08-06T12:27:59Z")
Hello everyone šŸ™‚ , I am using wandb to log multithreaded runs (using Jax), as it is not supported as of now all of the metrics are logged on the same run. However, as I log the timestep, I do have the right values for all of the threads (see picture). Would there be a way to, a posteriori, split a wandb run into multiple runs based on the timestep that I track (getting the i-th value of every metric to generate the i-th run)? Or is multithreading supported now so I can init a wandb run per-thread? The goal is to be able to use Jax to parallerize runs over different params/seeds (which it is already doing) while also logging on wandb (which it is only doing for one run at a time, the others being overwritten as a single wandb init can be used at once on a single process it seems). Thanks ![Capture dā€™eĢcran 2023-08-06 aĢ€ 14.24.51](https://us1.discourse-cdn.com/flex020/uploads/wandb/original/2X/8/8f3713d4e7c3edc03e2e83a8f1e6318975101fd6.png) ---
**Author:** ![uma-wandb](https://avatars.discourse-cdn.com/v4/letter/u/b77776/32.png) [@uma-wandb](https://community.wandb.ai/u/uma-wandb)\ **Post date:** [August 10, 2023, 5:57pm UTC](https://community.wandb.ai/t/how-to-split-runs-because-of-lack-of-multithreading-given-a-metric/4856/2 "2023-08-10T17:57:24Z")
Hey @yann-berthelot, since multithreading isnā€™t supported currently, I have a few suggestions: - If JAX supports this, I recommend having separate `wandb.init()` calls with different run ids in different threads in order to get different runs - you can generate different run\_ids using ```auto run = wandb.init( project="multithreading_project", id=wandb.util.generate_id(), ) ``` If youā€™d like to generate separate graphs with metrics at specific timesteps, you can do this a few ways. - You can download the charts as CSVā€™s and log the specific values you desire to new runs using `wandb.log()` - Alternatively, you can also do this through the UI, but these panels would remain in the same run. I attached a screenshot of where you can do this, after making duplicates of the panels you desire. ![Screen Shot 2023-08-10 at 10.57.01 AM](https://us1.discourse-cdn.com/flex020/uploads/wandb/original/2X/5/542574c442746188d78d8bc8c8677009a54828fc.png) Please let me know if either of these options work for you, and if you have any further questions! ---
**Author:** ![uma-wandb](https://avatars.discourse-cdn.com/v4/letter/u/b77776/32.png) [@uma-wandb](https://community.wandb.ai/u/uma-wandb)\ **Post date:** [August 15, 2023, 5:41am UTC](https://community.wandb.ai/t/how-to-split-runs-because-of-lack-of-multithreading-given-a-metric/4856/3 "2023-08-15T05:41:38Z")
Hi @yann-berthelot , since we have not heard back from you we are going to close this request. If you would like to re-open the conversation, please let us know! ---
**Author:** ![jucor](https://sea2.discourse-cdn.com/flex020/user_avatar/community.wandb.ai/jucor/32/552_2.png) [@jucor](https://community.wandb.ai/u/jucor)\ **Post date:** [August 18, 2023, 5:27pm UTC](https://community.wandb.ai/t/how-to-split-runs-because-of-lack-of-multithreading-given-a-metric/4856/4 "2023-08-18T17:27:32Z")
HI @uma-wandb Iā€™m also interested in this, for a different use case. Do you confirm wandb is thread-safe, in that you can have each thread have its own wandb run? ---
**Author:** ![yann-berthelot](https://avatars.discourse-cdn.com/v4/letter/y/6f9a4e/32.png) [@yann-berthelot](https://community.wandb.ai/u/yann-berthelot)\ **Post date:** [August 28, 2023, 12:39pm UTC](https://community.wandb.ai/t/how-to-split-runs-because-of-lack-of-multithreading-given-a-metric/4856/5 "2023-08-28T12:39:56Z")
Hello, I tried what you proposed (which only make the last run initialized log, the others staying empty) but I think I misunderstood how Jax was actually working it parallelization. As it is vectorizing the computations it is only processing a single batch of data in a single thread but with multiple sub-batches corresponding to each separate experiment. However your solution would surely work for multiprocessing, which I cannot experiment with at the moment, so I cannot say for sure. In order to work around this I built a script that fetches the ā€œmergedā€ run (containing the values for all experiments, as see above. Where each tilmestep has multiple values corresponding to each ā€œparallelā€ experiment.) and splits it in N different runs (by taking 1st element of every timestep for run #1, 2nd element of every timestep for run #2, ā€¦, N-th element of every timestep for run #N). So, assuming you have already run your job that uploads a run with multiple values per timestep (10 in my case), here is the code that Iā€™m using if that can help somebody (itā€™s not very general but itā€™s a start) : ```auto """ Extract multiple runs from a merged-wandb run due to lack of multithreading. See: https://community.wandb.ai/t/how-to-split-runs-because-of-lack-of-multithreading-given-a-metric/4856 """ import glob import json import os from typing import Any, Generator, Optional import wandb from tqdm import tqdm WandbRun = Any os.environ["WANDB_ENTITY"] = "yann-berthelot" def get_last_run(user_name: str, project_name: str): api = wandb.Api() runs = api.runs(f"{user_name}/{project_name}") return runs[0] # last run def split_run(run: WandbRun, num_splits: int) -> tuple[list, dict, str]: """ Split the last wandb run. Args: user_name (str): The user for which to select the run project_name (str): The wandb project run num_splits (int): The number of runs to split into Returns: tuple[list, dict, str]: The split runs, the config, and the original run name """ history, config, name = get_history_config_and_name_from_run(run) return ( [list(history)[i::num_splits] for i in range(num_splits)], config, name, ) def get_config_from_run(run: WandbRun) -> dict: """Extract config from a wandb run""" return {key: value["value"] for key, value in json.loads(run.json_config).items()} def get_history_from_run(run: WandbRun, page_size: int = int(1e6)) -> Generator: """ Extract history from wandb run Args: run (wandb.run): The wandb run to consider page_size (int, optional): How much steps to process at a time,\ the higher the better perf. Defaults to int(1e6). Returns: Generator: The history of the run """ return run.scan_history(page_size=page_size) def get_name_from_run(run: WandbRun) -> str: """Extract name from wandb run""" return run.name def get_history_config_and_name_from_run(run: WandbRun) -> tuple[Generator, dict, str]: """Extract history, config, and name from last wandb run with the given\ user and project""" return get_history_from_run(run), get_config_from_run(run), get_name_from_run(run) def upload_runs(project_name: str, run_name: str, runs: list, config: dict) -> None: """Build the runs locally then upload the collected runs""" for i, run in tqdm(enumerate(runs)): run_config = config run_config["seed"] = i wandb_run = wandb.init( project=project_name, name=f"{run_name}_{i}", config=config, reinit=True, mode="offline", ) # Build for step in tqdm(run, leave=False): wandb_run.log(step) wandb_run.finish() # Upload BASE_FOLDER = "./wandb" file = glob.glob(f"{BASE_FOLDER}/*{wandb_run.id}")[0] os.system(f"wandb sync --clean-force {file} ") def split_runs_and_upload_them( user_name: str, project_name_in: str, num_split: int, project_name_out: Optional[str] = None, ) -> None: """ Split the defined wandb run of the project/user into runs into the project_name_out. First run is the 1st element, then the 1 + num_split-th element etc ... Second run is the 2nd element, then the 2 + num_split-th element etc ... If no project_out is given, take the initial project. Args: user_name (str): The user to consider. project_name_in (str): The project to take the last run in. num_split (int): The number of splits to make. project_name_out (Optional[str], optional): _description_. Defaults to None. """ print("Splitting run") run = get_last_run( user_name, project_name_in ) # TODO :Be able to work with other runs? by name ? runs, config, name = split_run(run, num_split) if project_name_out is None: project_name_out = project_name_in print("Runs split. Uploading runs.") upload_runs(project_name_out, name, runs, config) print("Uploading done.") if __name__ == " __main__": split_runs_and_upload_them( os.environ["WANDB_ENTITY"], project_name_in="Benchmark delay merged", project_name_out="Benchmark delay merged out", num_split=10, # TODO : is it possible to infer? ) ``` I guess it would be nice to have such a functionality natively. Have a nice day, Yann ---
**Author:** ![system](https://us1.discourse-cdn.com/flex020/uploads/wandb/original/1X/366b649231631dbab896843020da0056074ac79d.png) [@system](https://community.wandb.ai/u/system)\ **Post date:** [October 27, 2023, 12:40pm UTC](https://community.wandb.ai/t/how-to-split-runs-because-of-lack-of-multithreading-given-a-metric/4856/6 "2023-10-27T12:40:39Z")
Closed on October 27, 2023, 12:40pm UTC This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.