On Wed, 09 Jun 2021 12:52:18 +0200, Thomas Hartwig wrote:
Hi Takashi,
I tried preempt already without success, it is working but not fully satisfactory.
Hm, and yet CONFIG_HZ=1000 works? Then something odd there, and this has to be identified before diving into the blind increase of HZ. Otherwise it's a cargo-science. Takashi
Real-Time did crash the system for unknown reason yet, this is why I asked for detailed specs about Real-Time differences, however the Real-Time kernel really sound overwhelming as long as I only need the Interrupt timer being faster.
BR Thomas
On 6/7/21 4:37 PM, Takashi Iwai wrote:
On Mon, 07 Jun 2021 15:54:31 +0200, Thomas Hartwig wrote:
Hi,
for some reason PREEMPT is configured for 250? Am I missing something or is it by error?
$: grep CONFIG_HZ /boot/config-5.3.18-lp152.75-preempt # CONFIG_HZ_PERIODIC is not set # CONFIG_HZ_100 is not set CONFIG_HZ_250=y # CONFIG_HZ_300 is not set # CONFIG_HZ_1000 is not set CONFIG_HZ=250
Basically HZ plays little role when the full preempt is enabled. Have you tested with kernel-preempt flavor as is? Give it a try once, if not done yet.
If it still doesn't suffice, you can try the RT kernel like kernel-rt in OBS Kernel:SLE15-SP3-RT repo, too.
Takashi
Thomas
On 6/7/21 3:00 PM, Takashi Iwai wrote:
Well, if HZ=1000 really helps, it implies that it's no requirement of the hard RT, and kernel-preempt flavor would work enough for that purpose.
AFAIK, kernel-preempt is available for Leap. And for TW, we're going to switch to the dynamic preempt, i.e. the preemption model is chosen via boot option.
Takashi