lkml.org 
[lkml]   [2019]   [Jan]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 0/2] Fix TSC issues on (some) AMD Ryzen based systems
From
Date
Dear Jan,


Thank you for adding me to the CC list.


Am 29.01.19 um 11:23 schrieb Jan H. Schönherr:
> My newly acquired AMD Ryzen Threadripper based system seems to have
> some TSC quirks, which go away once the system is up.
>
> Given the discussion in https://lkml.org/lkml/2019/1/28/1356
> I don't seem to be the only one, and it does not seem to be
> Threadripper specific.
>
> The first patch addresses presumably SMI interruptions, that occur
> on my system at a 60 Hz frequency. They take too long, making the
> existing code fail. The patch makes that code more resilient.
> (These interruptions go away at some point during boot; also proven
> by the fact, that I don't have any TSC issues, when kexecing into
> a new kernel.)
>
> The second patch prevents TSC going unstable when resuming from S3.
> This may have a similar source, but is certainly more weird: the
> TSC is observed to go backwards on CPU0 by about 200 to 500 cycles
> compared to other CPUs every once in a while, as long as its sibling
> (CPU16 in my case) hasn't been resumed yet. (I did some experiments
> with CPU hotplug before and after suspend, but apart from reproducing
> the issue and verifying the "fix", I got nowhere.)
>
> The patches are against v4.20.
>
> Jan H. Schönherr (2):
> x86/tsc: Allow quick PIT calibration despite interruptions
> cpu/hotplug: Unfreeze sibling CPU first on resume from S3
>
> arch/x86/kernel/tsc.c | 80 +++++++++++++++++++++++++------------------
> kernel/cpu.c | 34 ++++++++++++------
> 2 files changed, 70 insertions(+), 44 deletions(-)

I successfully tested both applied on Linus’ current master branch
(v5.0-rc4-1-g4aa9fc2a435a).

> [ 0.000000] DMI: HP HP EliteDesk 705 G4 MT/83E7, BIOS Q06 Ver. 02.04.01 09/14/2018
> [ 0.000000] tsc: Fast TSC calibration using PIT
> [ 0.000000] tsc: Detected 3616.864 MHz processor


Kind regards,

Paul

\
 
 \ /
  Last update: 2019-01-29 20:34    [W:0.077 / U:16.708 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site