A Global Switch To Kill Linux's CPU Spectre/Meltdown Workarounds?

[phoronix]

Phoronix: A Global Switch To Kill Linux's CPU Spectre/Meltdown Workarounds?

Something I have seen asked in our forums and elsewhere -- most recently on the kernel mailing list -- is whether there is a single kernel option that can be used for disabling all of the Spectre/Meltdown workarounds and any other performance-hurting CPU vulnerability workarounds...

http://www.phoronix.com/scan.php?page=news_item&px=Global-Switch-Skip-Spectre-Melt

[uid313]

Soon new CPUs are coming that is expected to have in-silicon mitigations for the Meltdown and Spectre hardware vulnerabilities.
Such as the upcoming Intel "Ice Lake" CPU.
Maybe also upcoming Ryzen.

[blae]

Phoronix: A Global Switch To Kill Linux's CPU Spectre/Meltdown Workarounds?

Something I have seen asked in our forums and elsewhere -- most recently on the kernel mailing list -- is whether there is a single kernel option that can be used for disabling all of the Spectre/Meltdown workarounds and any other performance-hurting CPU vulnerability workarounds...

http://www.phoronix.com/scan.php?pag...p-Spectre-Melt

thanks for this, was looking for it recently

[ryszardzonk]

for first two I would use nopti nospectre_v2 as they are simply shorter, but as for l1tf=off & no_stf_barrier it is first time I even hear about them...

[creative]

Thanks for this post. Please do not forget the games benchmarking, I know for at least some of us, gaming is a huge thing.

[Michael]

Thanks for this post. Please do not forget the games benchmarking, I know for at least some of us, gaming is a huge thing.

The gaming impact is quite small especially compared to I/O and other workloads, but the desktop CPU tests will probably include them.

[cl333r]

Thanks for this post. Please do not forget the games benchmarking, I know for at least some of us, gaming is a huge thing.

In games the CPU is rarely a performance issue, especially Vulkan games, all that matters is that you have a good GPU, lots GPU memory, lots of RAM memory and at least 2 or 4 cores on the CPU.

[mmstick]

In games the CPU is rarely a performance issue, especially Vulkan games, all that matters is that you have a good GPU, lots GPU memory, lots of RAM memory and at least 2 or 4 cores on the CPU.

Actually, most games are limited by the CPU, and usually because the game does not take advantage of as many threads as it could.

[apetresc]

How come `noretpoline` didn't make the list? Is it implicitly included in one of the other ones?

[darkbasic]

"pti=off spectre_v2=off l1tf=off nospec_store_bypass_disable no_stf_barrier"

Does it disable ALL the mitigations or some of them cannot be simply disabled?