News: 0001498318

  ARM Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life (Terry Pratchett, Jingo)

ARM64 SMT Control Patches Updated For The Linux Kernel

([Arm] 6 Hours Ago Toggling SMT On ARM)


While ARM-based SoCs with Simultaneous Multi-Threading (SMT) aren't too common, there do exist some such as select models of the Huawei Kunpeng server SoC with SMT or there HiSilicon Kirin 9000S. As such Huawei/HiSilicon engineers have been working to expose SMT controls on ARM64 for the Linux kernel.

Similar to Linux x86/x86_64 being able to toggle Simultaneous Multi-Threading support at run-time, the patches that have been worked on by Huawei and Huawei-owned HiSilicon to extend the Linux SMT controls to ARM64 so that the SMT behavior can be manipulated at run-time.

They are extending the run-time SMT controls to ARM64 on the basis of general security vulnerability concerns as well as for better single-thread CPU performance in some workloads and possibly CPU power consumption benefits.

The engineers have tested their ARM64 SMT controls both on real ACPI-based ARM64 server hardware with SMT as well as on ACPI/OF-based QEMU virtual machines.

The [1]v6 patches were posted today as the latest work on this support. The sixth revision to these patches bring various improvements as a result of earlier code review.



[1] https://lore.kernel.org/lkml/20241015021841.35713-1-yangyicong@huawei.com/


phoronix

The Poet Whose Badness Saved His Life
The most important poet in the seventeenth century was George
Wither. Alexander Pope called him "wretched Wither" and Dryden said of his
verse that "if they rhymed and rattled all was well".
In our own time, "The Dictionary of National Biography" notes that his
work "is mainly remarkable for its mass, fluidity and flatness. It usually
lacks any genuine literary quality and often sinks into imbecile doggerel".
High praise, indeed, and it may tempt you to savour a typically
rewarding stanza: It is taken from "I loved a lass" and is concerned with
the higher emotions.
She would me "Honey" call,
She'd -- O she'd kiss me too.
But now alas! She's left me
Falero, lero, loo.
Among other details of his mistress which he chose to immortalize
was her prudent choice of footwear.
The fives did fit her shoe.
In 1639 the great poet's life was endangered after his capture by
the Royalists during the English Civil War. When Sir John Denham, the
Royalist poet, heard of Wither's imminent execution, he went to the King and
begged that his life be spared. When asked his reason, Sir John replied,
"Because that so long as Wither lived, Denham would not be accounted the
worst poet in England."
-- Stephen Pile, "The Book of Heroic Failures"