Linux kernel CPU regression?

[18358414]

Hello,

 

I have an old Core 2 Duo processor (T7400) which, if I use the latest Linux kernel 4.18, will hang on boot.  Similarly, I have an Intel Atom N450 which doesn't quite hang on boot, however it is painfully slow to do anything (via CLI only) -- on boot, it seems to complain about an unstable clock.  I've noticed that on the Atom N450 processor, I can do a ping to 127.0.0.1 on the latest kernel and it takes on the order of 1-2 ms.  If I do the same ping test using the Linux kernel 4.14, I get pings on the order of 0.05ms.  Similarly, if I boot the Core 2 Duo to Linux 4.14, it boots just fine. 

 

Is there a CPU regression for these older CPUs on newer kernels that could be causing this?  The system hang on the core 2 processor is pretty bad, but the excessive ping times to localhost are also pretty bad.  Would be interested to hear if anyone else is having issues.

[wasab]

i got an amd fx 8320 here. im not sure if that is ancient but it certainly is an old chip. I dont see any sluggish boot cuz i run my OS on a Samsung ssd. The operating system i use is arch linux with kde plasma btw. I dont use the lts kernel so that thing is bleeding edge. 

[Madgemade]

I guess you are running exactly the same everything and just selecting between the two kernels at boot? It would be pretty surprising if the kernel actually had an issue. Possible though. You could try a (significantly) different distro with the same kernel version and if it was still happening then that would imply the kernel was at fault and not some kind of configuration that is not working well with the newer kernel.