upgrade vllm inference demo to use 0.7.0 and VLLM_USE_V1.

[2timesjay]

I upgraded to the newest version of vllm (0.7.0), which includes an alpha version of their substantially faster engine and a refactor to model configuration. If people are reusing these examples for demos and projects, this should be helpful.

Big speedup, especially at high concurrency. Here's some numbers from testing with Llama3-70B-fp8 on 1 H100:

vllm==0.7.0, VLLM_USE_V1=1

Max Parallelism	Number of Prompts	Average Latency (s)	p95 Latency (s)	Throughput (requests/s)
8	32	3.3245	3.5712	2.3654
16	32	3.7085	3.8151	4.2802
32	32	4.5872	4.6662	6.8342
64	64	5.8669	6.0471	10.4833
128	128	8.6023	8.8094	14.3457
256	256	14.7483	18.9714	13.2442

vllm=0.6.3post1

Max Parallelism	Number of Prompts	Average Latency (s)	p95 Latency (s)	Throughput (requests/s)
8	32	4.1822	4.3813	1.9079
16	32	4.6502	5.1558	3.1282
32	32	6.9919	9.2724	3.4463
64	64	11.4092	18.2382	3.4930
128	128	75.9388	90.1596	1.4170
256	256	93.1698	123.8264	2.0409

see full results: https://gist.github.com/2timesjay/ebc7773aa8fb01115172f37dae86bc47

Type of Change

• New example
• Example updates (Bug fixes, new features, etc.)
• Other (changes to the codebase, but not to examples)

Checklist

(all of these are satisfied by keeping the changes to a minimum)

• Example is testable in synthetic monitoring system, or lambda-test: false is added to example frontmatter (---)
  • Example is tested by executing with modal run or an alternative cmd is provided in the example frontmatter (e.g. cmd: ["modal", "deploy"])
  • Example is tested by running with no arguments or the args are provided in the example frontmatter (e.g. args: ["--prompt", "Formula for room temperature superconductor:"]
• Example is documented with comments throughout, in a Literate Programming style.
• Example does not require third-party dependencies to be installed locally
• Example pins its dependencies
  • Example pins container images to a stable tag, not a dynamic tag like latest
  • Example specifies a python_version for the base image, if it is used
  • Example pins all dependencies to at least minor version, ~=x.y.z or ==x.y
  • Example dependencies with version < 1 are pinned to patch version, ==0.y.z

Outside contributors

Jacob Jensen (2timesjay)

[charlesfrye]

Thanks for the PR! cc @jackcook

[jackcook]

Looks good to me! I did some benchmarking today to look at the effects of the new V1 engine and we're seeing similar improvements internally as well.

[bhaktatejas922]

theres a fair amount of things not implemented yet on v1, could be worth adding a disclaimer

[charlesfrye]

thanks for sharing this @2timesjay and for your comment @bhaktatejas922! we incorporated the changes and feedback into #1076 and #1078