PMC.DMC-620(3)

💖 PMC.DMC-620(3) 💖

hey bestie!! so like, this is a page from the Library Functions Manual and it's literally all about measuring the Arm DMC-620 Dynamic Memory Controller performance counter events. no cap, it's giving hardware nerd realness and i'm obsessed 💅✨

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🌸 LIBRARY 🌸

Performance Counters Library (libpmc, -lpmc) — it's right there in the name, bestie! 🫶

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✨ SYNOPSIS ✨

#include <pmc.h>

that's literally it, super clean, we love to see it 💖

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🦋 DESCRIPTION 🦋

okay so DMC-620 PMU counters can be configured to count any one of a defined set of hardware events. like, you pick your event, you count it, slay.

the Arm CoreLink DMC-620 Dynamic Memory Controller performance counters are documented in "Revision: r0p0", ARM CoreLink DMC-620 Dynamic Memory Controller Technical Reference Manual, ARM Limited, 2017. so if you wanna be a nerd about it, that's where the lore lives 📚✨

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💜 PMC Capabilities 💜

DMC-620 PMU counters support the following capabilities — here's the vibe check:

• PMC_CAP_CASCADE — No 🙅‍♀️
• PMC_CAP_EDGE — No
• PMC_CAP_INTERRUPT — Yes 💖
• PMC_CAP_INVERT — Yes ✨
• PMC_CAP_READ — Yes 🎀
• PMC_CAP_PRECISE — No
• PMC_CAP_SYSTEM — Yes 🦋
• PMC_CAP_TAGGING — No
• PMC_CAP_THRESHOLD — Yes 🌸
• PMC_CAP_USER — No
• PMC_CAP_WRITE — Yes 💅

so like, interrupt? yes. system? yes. write? yes. user? absolutely not, we don't do that here 😤

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🌈 Event Qualifiers 🌈

event specifiers for these PMCs support the following common qualifiers — periodt:

• inc=value — a two-bit value that controls the direction of count for the PMC. the behavior depends on the selected event, so don't @ me if you get it wrong bestie 😭
• inv — invert the sense of comparison. it's giving "flip it and reverse it" 🔄
• match=value — count only events matched by value. like a filter for your counting, we stan a selective queen 👑
• mask=qualifier — allows you to apply a qualifier mask to the compared value. fancy! 💅

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🧚 Class Name Prefix 🧚

these PMCs use a class name prefix of "DMC620_CD2_" or "DMC620_C_". remember that, it's important iykyk 💖

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⭐ Event Specifiers ⭐

the following PMC events are available — here's the full list, no skips, no cuts, all love:

clkdiv2_cycle_count
clkdiv2_allocate
clkdiv2_queue_depth
clkdiv2_waiting_for_wr_data
clkdiv2_read_backlog
clkdiv2_waiting_for_mi
clkdiv2_hazard_resolution
clkdiv2_enqueue
clkdiv2_arbitrate
clkdiv2_lrank_turnaround_activate
clkdiv2_prank_turnaround_activate
clkdiv2_read_depth
clkdiv2_write_depth
clkdiv2_highhigh_qos_depth
clkdiv2_high_qos_depth
clkdiv2_medium_qos_depth
clkdiv2_low_qos_depth
clkdiv2_activate
clkdiv2_rdwr
clkdiv2_refresh
clkdiv2_training_request
clkdiv2_t_mac_tracker
clkdiv2_bk_fsm_tracker
clkdiv2_bk_open_tracker
clkdiv2_ranks_in_pwr_down
clkdiv2_ranks_in_sref
clk_cycle_count
clk_request
clk_upload_stall

that's a LOT of events, but we're not skipping any of them because every single one matters 💯✨

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🎀 SEE ALSO 🎀

• pmc(3)
• pmc.amd(3)
• pmc.atom(3)
• pmc.core(3)
• pmc.core2(3)
• pmc.corei7(3)
• pmc.corei7uc(3)
• pmc.iaf(3)
• pmc.soft(3)
• pmc.tsc(3)
• pmc.westmere(3)
• pmc.westmereuc(3)
• pmc_cpuinfo(3)
• pmclog(3)
• hwpmc(4)

like, go read them if you want more context bestie, they're all connected 🫶

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👑 HISTORY 👑

so the pmc library first appeared in FreeBSD 6.0. iconic behavior honestly.

and the pmc.dmc-620 driver was added in FreeBSD 14.0. newer but already making moves 💅

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🌟 AUTHORS 🌟

the Performance Counters Library (libpmc, -lpmc) library was written by:

• Joseph Koshy <jkoshy@FreeBSD.org>
• Oleksandr Rybalko <ray@FreeBSD.org>

the DMC-620 PMU driver was sponsored by Ampere Computing LLC. shoutout to them for funding the vibes 💖

and this manual page was written by Oleksandr Rybalko <ray@FreeBSD.org>. thank you for your service king 🫡✨

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and that's literally the whole page bestie! now go count some events and slay 💅💖✨

Debian · Jul 22, 2022 — mwah, hope this helped, love u bye!! 💜🦋🌸