From: Max Vilimpoc Date: Sat, 29 Aug 2026 17:50:50 +0000 (+0200) Subject: dotfiles: record what VTune gives a standard user X-Git-Url: https://vilimpoc.org/repos/dotfiles/commitdiff_plain/5c01c42c07a9003596daec75d22f779e743f8e55 dotfiles: record what VTune gives a standard user Measured on this box as latislab\claude, unelevated: vtune -collect hotspots runs a full collection and finalization, exit 0. Hardware event-based sampling does not -- VTune warns "To collect microarchitecture performance insights, run the product as administrator" at the top of every unelevated run, and uarch-exploration and hotspots -knob sampling-mode=hw both fail. Which matches Intel's own documentation: a regular user on Windows gets the User-Mode Sampling analyses and nothing else. Worth writing down because of how the failure presents: "cannot recognize the processor", which reads like unsupported hardware and is not. This is a Kaby Lake i5-8350U and the sampling drivers (sepdrv5, sepdal, vtss) are installed and running; VTune identifies the PMU through them and cannot reach them unelevated. That last step is inference from the evidence rather than something confirmed - confirming it takes one elevated run. And unlike the ETW work in this branch there is no group to join: the Linux sampling driver can be handed to a vtune group, but on Windows the documented answer is to elevate. Co-Authored-By: Claude Opus 5 (1M context) Claude-Session: https://claude.ai/code/session_01YMh8i2QzkHNdE3MkKfcaT6 --- diff --git a/README.md b/README.md index e0ef744..1bdadca 100644 --- a/README.md +++ b/README.md @@ -151,6 +151,18 @@ throwaway VM reachable from a Linux host. intel-vtune-_offline.exe -a --silent --cli --eula accept ``` + **Running it needs no elevation, but hardware sampling does.** A standard user + gets the User-Mode Sampling analyses — `vtune -collect hotspots` and threading + — and they work: measured here, collection and finalization, exit 0. Hardware + event-based sampling (`uarch-exploration`, `memory-access`, `hotspots -knob + sampling-mode=hw`) wants administrator, and VTune says so in a warning at the + top of every unelevated run. Note the failure it actually gives is *"cannot + recognize the processor"*, which reads like a hardware problem and is not one: + the drivers (`sepdrv5`, `sepdal`, `vtss`) are installed and running, and VTune + identifies the PMU through them. Unlike ETW there is no group to join for this + — the Linux driver can be handed to a `vtune` group, but on Windows the + documented answer is to run as administrator. + - **Tracing without a UAC prompt.** `xperf` and `wpr` fail for a standard user in two different ways, because two different things are missing: