Enable Async output process for HPU

[zhouyu5]

FILL IN THE PR DESCRIPTION HERE

This PR refer to #7049 to implement Asynchronous Output Processor on HPU. It is open by default, to disable it, please pass the --disable_async_output_proc flag.

From my local test on latest habana_main branch(commit 29fb5ed), the throughput improves from 3847 TPS to 4011 TPS.

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[michalkuligowski]

Where is this set?
Vllm code names it output_proc_callback_fn shouldnt we keep the name?

[zhouyu5]

@michalkuligowski
It is first set in llm_engine.py, see:

if model_config.use_async_output_proc:
    process_model_outputs = weak_bind(self._process_model_outputs)
    self.async_callbacks = [
        partial(process_model_outputs,
                ctx=self.scheduler_contexts[v_id])
        for v_id in range(self.parallel_config.pipeline_parallel_size)
    ]
...
if allow_async_output_proc:
    execute_model_req.async_callback = self.async_callbacks[
        virtual_engine]

then pass to worker_base.py, which is inherited by HabanaWorker,

if execute_model_req.async_callback:
    model_input = dataclasses.replace(  # type: ignore
        model_input,
        async_callback=execute_model_req.async_callback)

For its name, it is initially called output_proc_callback_fn, but in vllm's latest code, it's changed to async_callback, since it could involve other operations, not only output processing, see this comment in PR#7911,

[michalkuligowski]

Formatting issues

[zhouyu5]

Thanks. Formatted now. @michalkuligowski