Make hybrid cache exportable
Author: tugsbayasgalan
Pull request: yes

# What does this PR do?

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Fixes # (issue)


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There seems to be no throughput degradation vs `main` ✅ 

`main`:
<img width="542" alt="Screenshot 2025-04-22 at 10 28 32" src="https://github.com/user-attachments/assets/9c3a7d77-48ed-4b9a-b4c7-00b870e323a6" />

this PR:
<img width="566" alt="Screenshot 2025-04-22 at 10 23 26" src="https://github.com/user-attachments/assets/28d6e7c3-6420-46d8-842e-a4da8da28f68" />


<details>
  <summary>Test script</summary>

  ```py
  import copy
import os
import torch
from torch.utils import benchmark

from transformers import AutoTokenizer, AutoModelForCausalLM

os.environ["TOKENIZERS_PARALLELISM"] = "false"

# Benchmarking settings
BSZ = [1, 4]
NEW_TOK = [16, 256]
N_ITER = 10
MODEL_ID = "google/gemma-2-2b-it"
CACHE_IMPLEMENTATION = "hybrid"

# Other constants
FRANCE_ARTICLE = (
    "
Marseille, France (CNN)The French prosecutor leading an investigation into the crash of Germanwings Flight "
    "9525 insisted Wednesday that he was not aware of any video footage from on board the plane. Marseille "
    "prosecutor Brice Robin told CNN that \"so far no videos were used in the crash investigation.\" He added, \"A "
    "person who has such a video needs to immediately give it to the investigators.\" Robin\'s comments follow claims "
    "by two magazines, German daily Bild and French Paris Match, of a cell phone video showing the harrowing final "
    "seconds from on board Germanwings Flight 9525 as it crashed into the French Alps. All 150 on board were killed. "
    "Paris Match and Bild reported that the video was recovered from a phone at the wreckage site. The two "
    "publications described the supposed video, but did not post it on their websites. The publications said that "
    "they watched the video, which was found by a source close to the investigation. \"One can hear cries of 'My God' "
    "in several languages,\" Paris Match reported. \"Metallic banging can also be heard more than three times, "
    "perhaps of the pilot trying to open the cockpit door with a heavy object.  Towards the end, after a heavy "
    "shake, stronger than the others, the screaming intensifies. Then nothing.\" \"It is a very disturbing scene,\" "
    "said Julian Reichelt, editor-in-chief of Bild online. An official with France\'s accident investigation agency, "
    "the BEA, said the agency is not aware of any such video. Lt. Col. Jean-Marc Menichini, a French Gendarmerie "
    "spokesman in charge of communications on rescue efforts around the Germanwings crash site, told CNN that the "
    "reports were \"completely wrong\" and \"unwarranted.\" Cell phones have been collected at the site, he said, "
    "but that they \"hadn\'t been exploited yet.\" Menichini said he believed the cell phones would need to be sent "
    "to the Criminal Research Institute in Rosny sous-Bois, near Paris, in order to be analyzed by specialized "
    "technicians working hand-in-hand with investigators. But none of the cell phones found so far have been sent "
    "to the institute, Menichini said. Asked whether staff involved in the search could have leaked a memory card "
    "to the media, Menichini answered with a categorical \"no.\" Reichelt told \"Erin Burnett: Outfront\" that he "
    "had watched the video and stood by the report, saying Bild and Paris Match are \"very confident\" that the clip "
    "is real. He noted that investigators only revealed they\'d recovered cell phones from the crash site after "
    "Bild and Paris Match published their reports. \"That is something we did not know before. ... Overall we can "
    "say many things of the investigation weren\'t revealed by the investigation at the beginning,\" he said. What "
    "was mental state of Germanwings co-pilot? German airline Lufthansa confirmed Tuesday that co-pilot Andreas "
    "Lubitz had battled depression years before he took the controls of Germanwings Flight 9525, which he\'s "
    "accused of deliberately crashing last week in the French Alps. Lubitz told his Lufthansa flight training "
    "school in 2009 that he had a \"previous episode of severe depression,\" the airline said Tuesday. Email "
    "correspondence between Lubitz and the school discovered in an internal investigation, Lufthansa said, "
    "included medical documents he submitted in connection with resuming his flight training. The announcement "
    "indicates that Lufthansa, the parent company of Germanwings, knew of Lubitz's battle with depression, allowed "
    "him to continue training and ultimately put him in the cockpit. Lufthansa, whose CEO Carsten Spohr previously "
    "said Lubitz was 100% fit to fly, described its statement Tuesday as a \"swift and seamless clarification\" and "
    "said it was sharing the information and documents -- including training and medical records -- with public "
    "prosecutors. Spohr traveled to the crash site Wednesday, where recovery teams have been working for the past "
    "week to recover human remains and plane debris scattered across a steep mountainside. He saw the crisis center "
    "set up in Seyne-les-Alpes, laid a wreath in the village of Le Vernet, closer to the crash site, where grieving "
    "families have left flowers at a simple stone memorial. Menichini told CNN late Tuesday that no visible human "
    "remains were left at the site but recovery teams would keep searching. French President Francois Hollande, "
    "speaking Tuesday, said that it should be possible to identify all the victims using DNA analysis by the "
    "end of the week, sooner than authorities had previously suggested. In the meantime, the recovery of the "
    "victims' personal belongings will start Wednesday, Menichini said. Among those personal belongings could be "
    "more cell phones belonging to the 144 passengers and six crew on board. Check out the latest from our "
    "correspondents . The details about Lubitz's correspondence with the flight school during his training were "
    "among several developments as investigators continued to delve into what caused the crash and Lubitz\'s "
    "possible motive for downing the jet. A Lufthansa spokesperson told CNN on Tuesday that Lubitz had a valid "
    "medical certificate, had passed all his examinations and \"held all the licenses required.\" Earlier, a "
    "spokesman for the prosecutor\'s office in Dusseldorf, Christoph Kumpa, said medical records reveal Lubitz "
    "suffered from suicidal tendencies at some point before his aviation career and underwent psychotherapy before "
    "he got his pilot's license. Kumpa emphasized there's no evidence suggesting Lubitz was suicidal or acting "
    "aggressively before the crash. Investigators are looking into whether Lubitz feared his medical condition "
    "would cause him to lose his pilot's license, a European government official briefed on the investigation told "
    "CNN on Tuesday. While flying was \"a big part of his life,\" the source said, it\'s only one theory being "
    "considered. Another source, a law enforcement official briefed on the investigation, also told CNN that "
    "authorities believe the primary motive for Lubitz to bring down the plane was that he feared he would not "
    "be allowed to fly because of his medical problems. Lubitz's girlfriend told investigators he had seen an eye "
    "doctor and a neuropsychologist, both of whom deemed him unfit to work recently and concluded he had "
    "psychological issues, the European government official said. But no matter what details emerge about his "
    "previous mental health struggles, there's more to the story, said Brian Russell, a forensic psychologist. "
    "\"Psychology can explain why somebody would turn rage inward on themselves about the fact that maybe they "
    "weren't going to keep doing their job and they're upset about that and so they're suicidal,\" he said. \"But "
    "there is no mental illness that explains why somebody then feels entitled to also take that rage and turn it "
    "outward on 149 other people who had nothing to do with the person's problems.\" Germanwings crash compensation: "
    "What we know . Who was the captain of Germanwings Flight 9525? CNN's Margot Haddad reported from Marseille and "
    "Pamela Brown from Dusseldorf, while Laura Smith-Spark wrote from London. CNN's Frederik Pleitgen, Pamela "
    "Boykoff, Antonia Mortensen, Sandrine Amiel and Anna-Maja Rappard contributed to this report."
)


tokenizer = AutoTokenizer.from_pretrained(MODEL_ID, padding_side="left")
model = AutoModelForCausalLM.from_pretrained(MODEL_ID, torch_dtype=torch.bfloat16).to("cuda")
prompt_length = tokenizer([FRANCE_ARTICLE], return_tensors="pt").input_ids.shape[1]
label_ms_per_token = f"Throughput (time/foward pass, prompt = {prompt_length} tokens)"
label_first_step = f"First call (time, prompt = {prompt_length} tokens)"


def print_results(all_results):
    print("\n")
    compare = benchmark.Compare(all_results)
    compare.trim_significant_figures()
    compare.colorize(rowwise = True)
    compare.print()


def time_generate_call(model, task, ms_per_token, first_step, compile=False):
    for bsz in BSZ:
        for max_new_tokens in NEW_TOK:
            input_ids = tokenizer([FRANCE_ARTICLE] * bsz, return_tensors="pt").to("cuda")
            description = f"batch size, max_new_tokens: {bsz, max_new_tokens}"
            task_spec_ms_per_token = benchmark.TaskSpec(
                stmt="", setup="", description=task, label=label_ms_per_token, sub_label=description
            )
            task_spec_ms_first_step = benchmark.TaskSpec(
                stmt="", setup="", description=task, label=label_first_step, sub_label=description
            )

            # generate EXACTLY `max_new_tokens` tokens (no early termination due to `eos_token_id`)
            generation_kwargs = {
                "max_new_tokens": max_new_tokens,
                "min_new_tokens": max_new_tokens,
                "eos_token_id": None,
                "do_sample": False,
                "cache_implementation": CACHE_IMPLEMENTATION if compile else None
            }
            generation_config = copy.deepcopy(model.generation_config)
            generation_config.update(**generation_kwargs)

            torch.compiler.reset()
            results = []
            for _ in range(N_ITER):
                start = torch.cuda.Event(enable_timing=True)
                end = torch.cuda.Event(enable_timing=True)
                start.record()
                gen_out = model.generate(**input_ids, generation_config=generation_config)
                end.record()
                torch.cuda.synchronize()
                total_time = start.elapsed_time(end) / 1000  # time in seconds
                time_per_forward = total_time / max_new_tokens
                assert gen_out.shape[1] == max_new_tokens + prompt_length
                results.append(time_per_forward)

            ms_per_token.append(benchmark.Measurement(1, results[3:], task_spec_ms_per_token, metadata=None))
            first_step.append(benchmark.Measurement(
                1, [results[0] * max_new_tokens], task_spec_ms_first_step, metadata=None)
            )
            print_results(ms_per_token)
            print_results(first_step)
            print("*" * 80)


ms_per_token = []
first_step = []

# eager
with torch.compiler.set_stance("force_eager"):
    time_generate_call(model, "eager", ms_per_token, first_step)

# compiled
time_generate_call(model, "compiled", ms_per_token, first_step, compile=True)
  ```
</details>