PSST(1)

💅 PSST — like, the manual, but make it make sense 💅

okay bestie, gather round, because we're about to talk about psst, aka the Power Stress and Shaping Tool 🎀. she's a command-line girlie and she's here to run the show on your terminal. no cap.

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✨ SYNOPSIS ✨

psst [options <value>]

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🌸 DESCRIPTION 🌸

so. the Power Stress and Shaping Tool (PSST) is literally a controlled power 'virus' 💀 — but like, in a cute, intentional way — built for Intel SoC components like the CPU and the GPU.

the whole vibe? you're subjecting the SoC to different run-time-varying utilization levels so you can analyze what happens 🔥. and how do we do that? by controlled duty-cycling of utilization into a specific contour. the simplest contour is just... fixed low utilization. and that's actually super useful, bestie, because it lets you do simple stuff like logging system parameters at a fixed low overhead even when your polling intervals are tiny (like, milliseconds small) ⏱️.

and if you want to go bigger? study governors, workloads, e.t.c. — all of that is possible by applying different power shape contours and options. main character energy only 👑.

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⭐ OPTIONS ⭐

• -C, --cpumask CPUMASK — CPUMASK is a hexadecimal bit mask of the cpu you selected. (like, a1 selects cpu 0, 5, and 7 🫶). default: every online cpu, maximum 1024.
• -p, --poll-period pollperiod — pollperiod says how long the period for logging is, in milliseconds. default is 500 ms.
• -d, --duration m — sets duration m, in milliseconds, for how long psst runs. default is 3600000 — that's 1 hour, if math isn't your thing 💖.
• -l, --log-file path — gives the full path to the logfile. default is /var/log/psst.csv.
• -v, --verbose — turns on verbose mode. (default: disabled when args specified.)
• -V, --version — prints version, periodt.
• -T, --track-max-cpu — tracks the cpu# with maxed freq during the poll period 👀.
• -h, --help — prints help.
• -s, --shape-func shape-func,arg — specifies the power shape function and its argument. here's the whole menu, no gatekeeping:
  • single-step,v — where v is load step height [C0%]. (default shape: single-step,0.1)
  • sinosoid,w,a — where w is wavelength [seconds] and a is the amplitude (max load %)
  • stair-case,v,u — where v is load step height [C0%], u is step length (sec)
  • single-pulse,v,u — where v is load step height [C0%], u is step length (sec)
  • linear-ramp,m — where m is the slope (load/sec)
  • saw-tooth,m,a — slope m (load/sec); reversed after max a% or min(0.1)%

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🌈 EXAMPLES 🌈

1. use psst just for logging various power/thermal parameters:

sudo psst  # same as $./psst -s single-step,0.1 -p 500 -v

2. linear ramp CPU power with slope 3% usage-per-sec applied for cpu 1 and 3, polling and reporting every 700mS, output on termial, running for 33 seconds:

sudo psst -s linear-ramp,3 -C a -p 700 -d 33000 -v

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🦋 AUTHOR 🦋

Started by Noor Mubeen 💜

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🎀 COPYRIGHT 🎀

Copyright © 2017, Intel Corporation License GPLv2: GNU GPL version 2

This is free software: you are free to change and redistribute it.

There is NO WARRANTY, to the extent permitted by law. Or, say, there is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

fr fr, that no-warranty thing is not a bit — it's the real deal, bestie. read it twice 🙈.

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and that's the whole page, angel 💖 this cutie dropped on November 28, 2017, and it's living under the General Commands Manual section — the manual name is right there in the header: PSST(1). go forth and stress some silicon responsibly, iykyk ✨🌸