Mailinglist Archive: opensuse-factory (439 mails)

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Re: [opensuse-factory] Huge single-core performance loss with spectre v2 mitigation enabled (it's the default)
On Wed, 2019-04-10 at 14:35 +0200, Michael Pujos wrote:
On 4/10/19 1:53 PM, Jiri Slaby wrote:
On 10. 04. 19, 1:46, Michael Pujos wrote:

Even then, your CPU is Coffee Lake and that should have support for
EIBRS, but it does not according to the output:
* Enhanced IBRS (IBRS_ALL)
* CPU indicates ARCH_CAPABILITIES MSR availability: NO
* ARCH_CAPABILITIES MSR advertises IBRS_ALL capability: NO

I am not sure what is going on with your CPU here. Maybe EIBRS was
not
released for your CPU yet.

thanks,

Interesting. No idea either why it is not supported.
The laptop is up to date in term of BIOS and other system updates (I
updated if fully with Lenovo Vantage on Windows 10).

I guess you have the ucode-intel package installed? On my Tumbleweed,
that is:
$ rpm -qa|grep ucode-intel
ucode-intel-20190312-1.1.x86_64

You can also check whether microcode is being updated or not during
boot, e.g.:

$ dmesg |grep -i microcode
[ 0.000000] microcode: microcode updated early to revision 0x9a, date =
2018-07-16
[ 1.484930] microcode: sig=0x806e9, pf=0x40, revision=0x9a
[ 1.484955] microcode: Microcode Update Driver: v2.2.

All that being said, I don't remember which CPU families were expected
to have "Enhanced IBRS". I don't have it neither on i7-7560U nor on
W-2125 (Kaby Lake and Skylake, I think).

Regards
--
Dario Faggioli, Ph.D
http://about.me/dario.faggioli
Virtualization Software Engineer
SUSE Labs, SUSE https://www.suse.com/
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