Problemsby IbisTrouble with vLLM performance
MLOps3 posts from 3 people3d active+00 posts in the last 7 days, 2 the 7 days before (fading)
Posts per day
The posts behind it
3, newest first[Performance]: Waiting requests re-walk their whole prefix-cache hit on every scheduling step### Proposal to improve performance When a waiting request cannot be admitted, which is typical under KV-cache pressure, it stays at the head of the waiting queue and `KVCacheManager.get_computed_blocks` → `find_longest_cache_hit` runs again on every step. The walk probes the...vllm-project/vllm · apex-mochen3 repliesOpen ↗[Performance][NIXL] BLHNC MLA caches lost whole-row registration in #53781 and now need more NIXL descriptors than LBHNC## Your current environment - GLM-5.3 (78 MLA + 21 indexer layers) with a DFlash2 draft (6 layers, GQA, 8 KV heads, fp8 KV, k=4). - Prefill DEP8 (TP1 per rank). Decode TP4. Pull-mode `NixlConnector`, GPU-resident KV (no host buffer). - vLLM main @ `4e0a414c44`, plus #58471 (GQA...vllm-project/vllm · stu-cao2 repliesOpen ↗VLLM 4x rtx 3060 vs 8x rtx 3060 performance loss...beyond 4 GPUs will drastically hurt my token generation speeds because of the PCIe bottleneck? But is that regardless of what GPUs I'm running? . I know for example RTX 3090 needs more PCIE bandwidth because it's much more performant and will spit out much more data that needs...r/LocalLLaMA · u/snakeat3rrOpen ↗
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About this problem
Evidence
3 posts from 3 people in 2 places, about 1 a week over 20 days. Mostly on vllm-project/vllm, r/LocalLLaMA. Tools named alongside: Qwen, llama.cpp.
Frustration Frustration 0 of 3· Seen on GitHub issues, Reddit
How it was grouped
Posts about vLLM with no known issue, sharing the word "performance". First post Sep 25, 2026, latest Oct 14, 2026. Corroborated: 3 or more posts from 2 or more people or places. Method
Other vLLM problems
vLLM upgrades break working setupsTrouble with vLLM decodingRunning vLLM locally hits memory and speed limitsvLLM GPU access and drivers are painfulRAG on vLLM returns irrelevant or missing contextTrouble with vLLM installationvLLM runs out of context on real workFine-tuning vLLM is costly and unpredictablevLLM runs out of memoryvLLM lock-in makes switching costlyvLLM users keep filing bugs
History
steady to fading
Trouble with vLLM performance (3 posts)