Benchmarking The Performance Impact Of Speculative Store Bypass Disable For Spectre V4 On Intel Core i7

[phoronix]

Phoronix: Benchmarking The Performance Impact Of Speculative Store Bypass Disable For Spectre V4 On Intel Core i7

In late May Spectre V4 was made public and coinciding with the public reveal was the Linux kernel patches for the Speculative Store Bypass Disable (SSBD) mode for mitigating this latest side-channel attack. For SSBD on Intel CPUs, updated microcode is required and those patched microcode files are now being delivered down through new BIOS updates from motherboard vendors. In recent days with seeing ASUS motherboards get the updated supported, I decided to run some initial Core i7 Coffeelake benchmarks with/without the SSBD support being enabled in the Linux kernel.

http://www.phoronix.com/vr.php?view=26506

[nuetzel]

Please test on older 'commodity' hardware (CPUs) and sum it up. (Here 10%, there 10%, etc...)
Thanks!

[schmidtbag]

Does "vulnerable" include previous Spectre and Meltdown patches, or does that mean before all patches? Because if this is the former, that's actually quite a significant performance loss, when you account for all the other performance losses of the other patches.

[Michael]

Does "vulnerable" include previous Spectre and Meltdown patches, or does that mean before all patches? Because if this is the former, that's actually quite a significant performance loss, when you account for all the other performance losses of the other patches.

From the system table:

Vulnerable: KPTI + __user pointer sanitization + Full generic retpoline IBPB IBRS_FW Protection
SSBD On: KPTI + __user pointer sanitization + Full generic retpoline IBPB IBRS_FW + SSB disabled Protection

Only SSBD is being toggled in this article, the others left at their defaults.

[Ehvis]

Vulnerable: KPTI + __user pointer sanitization + Full generic retpoline IBPB IBRS_FW Protection
SSBD On: KPTI + __user pointer sanitization + Full generic retpoline IBPB IBRS_FW + SSB disabled Protection

Is there a reference with all of these Spectre/Meltdown patches disabled? On a home/gaming system I'd rather have the performance than a few patches that are essentially nonsense for my situation.

[Michael]

Is there a reference with all of these Spectre/Meltdown patches disabled? On a home/gaming system I'd rather have the performance than a few patches that are essentially nonsense for my situation.

Yes some from 4.15~4.16 https://www.phoronix.com/scan.php?page=search&q=KPTI

[Xaero_Vincent]

Sad that all these side channel and speculative execution vulnerability patches add up to a fairly notable loss of performance across various workloads when combined all together. Maybe time to look at CPU overclocking to help offset the losses.