[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-10-25 Thread Ubuntu Kernel Bot
This bug is awaiting verification that the linux-nvidia- tegra/6.8.0-1001.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-nvidia-tegra' to 'verification-done-noble-linux-

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-03-28 Thread Launchpad Bug Tracker
This bug was fixed in the package linux - 6.8.0-20.20 --- linux (6.8.0-20.20) noble; urgency=medium * noble/linux: 6.8.0-20.20 -proposed tracker (LP: #2058221) * Noble update: v6.8.1 upstream stable release (LP: #2058224) - x86/mmio: Disable KVM mitigation when X86_FEATURE_CL

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-03-07 Thread Andrea Righi
** Changed in: linux (Ubuntu Noble) Status: New => Fix Committed -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2051342 Title: Enable lowlatency settings in the generic kernel St

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-02-07 Thread Andrea Righi
@turner basically any type of I/O workload can benefit from the HZ=1000 change, I haven't posted any test result, because in the scope of this proposal I wanted to focus mainly at the regression potential for CPU- intensive workloads and the benefits in terms of power consumption (this one as a pos

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-02-06 Thread Shane Turner
I haven’t spotted any tests that show a workload with a significant improvement shown here, on discourse, or Phoronix. Am I incorrect? Please keep in mind that I’m not suggesting that this initiative not move forward as there appears to be plenty of evidence being built up suggesting that there is

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-02-06 Thread Andrea Righi
More tests and results available here: https://discourse.ubuntu.com/t/enable-low-latency-features-in-the- generic-ubuntu-kernel-for-24-04/42255 -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bug

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-02-01 Thread Andrea Righi
@andysem yes that is also another possibility. The idea is to do a lot of tests and if we find that there's a remote possibility to introduce significant performance regressions in certain cases we can still keep HZ=250, but definitely go with the other options. -- You received this bug notificat

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-02-01 Thread Lastique
@arighi: Did you consider applying lowlatency settings to generic kernel but keeping CONFIG_HZ=250? I suspect, the majority of desktop usage issues (i.e. responsiveness) would be solved by `preempt=full rcu_nocbs=all` being the default (or whatever the equivalent boot options are). While keeping C

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-31 Thread Doug Smythies
I redid the Phoronix Stress-NG 0.16.04: Socket Activity test, the one that showed such a dramatic difference in their test. I increased to number of test runs from 3 to 10 and time per run from 30 to 60 seconds. I got: 250Hz kernel (generic): 6608.74 Bogo Op/s, Deviation 0.56% 1000Hz kernel (lowla

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-31 Thread pauldoo
The generic Ubuntu kernel has dynamic preempt enabled. This allows the preemption model to be changed at runtime between: none, voluntary (the default), and full. It would be super interesting to test what impact this has for latency sensitive workloads, and whether this can help you make the low

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-30 Thread Lastique
While testing locally, I have found this problem: https://bugs.launchpad.net/ubuntu/+source/linux-signed-lowlatency- hwe-6.5/+bug/2051733 If this is indeed a valid bug and not something weirdly specific to my system, I'd say `nohz_full` is non-functional. -- You received this bug notification be

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-30 Thread Doug Smythies
For the Stress-NG 0.16.04: pts/stress-ng-1.11.0 [Test: Socket Activity] I get: 6633.31 Bogo Ops/s on a 1000Hz kernel. 0.9% improvement. 6572.92 Bogo Ops/s on a 250 Hz kernel. I did this in a hurry, and will re-test tonight or tomorrow. -- You received this bug notification because you are a mem

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-30 Thread Andrea Righi
@andysem correct, without `nohz_full` specified at boot CONFIG_NO_HZ_FULL has no effect, except for the little extra overhead that it's adding to the tick handler (there is still some overhead with this option enabled, even if it's not used). That's why I'd like to measure the time spent in some of

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-30 Thread Lastique
I couldn't find this in the benchmark description on Phoronix, so I'm assuming the lowlatency kernel was booted with default parameters. Which means CONFIG_NO_HZ_FULL basically had no effect. This is probably fair for most users who won't specify `nohz_full` kernel parameter and will observe the pe

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-30 Thread Andrea Righi
@colin-king noticed, I just left a thank you message in the article. I'll still do the tests, but it's nice to see that someone else is contributing to this! Another thing that I'd like to measure is to bpftrace the time spent in the tick handler before and after these changes applied, because we

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-30 Thread Colin Ian King
Looks like Michael Larabel has done some analysis for you already :-) https://www.phoronix.com/news/Ubuntu-Generic-LL-Kernel -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2051342 Title:

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-29 Thread Colin Ian King
@Andrea, that's a good start, but it may be worth running some of the Phoronix Tests too as they are a good spread of use cases. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2051342 Titl

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-29 Thread Andrea Righi
@colin-king thanks! Any suggestion in particular? I was thinking to lmbench, netperf and fio. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2051342 Title: Enable lowlatency settings in

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-29 Thread Andrea Righi
@dsmythies thank you so much for sharing the results of your tests, really useful info! I'm planning to do more tests setting the performance governor, I've been doing my initial tests only with the default Ubuntu settings, that means with the "Balanced" power mode enabled (that I think it's using

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-29 Thread Colin Ian King
It may be worth trying a wider range of synthetic benchmarks to see how it affects scheduling, I/O, RCU and power consumption. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2051342 Title:

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-28 Thread Doug Smythies
Before my post yesterday, I had never used the stress-ng utility, and only did so to repeat the originally posted test case. However, there was run to run variability with the stress-ng test that I could not understand for a 100% user, 0% system, type program. I decided to retest using one my own C

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-27 Thread Doug Smythies
I found this bug report by accident, while searching for something else. I pretty much only use mainline kernels and only 1000 Hertz. I support this proposed default Ubuntu kernel configuration change. The tick ISR is incredibly efficient (less than 2 uSec on my test system), and I do not understa

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-26 Thread Andrea Righi
** Description changed: [Impact] Ubuntu provides the "lowlatency" kernel: a kernel optimized for applications that have special "low latency" requirements. Currently, this kernel does not include any specific UBUNTU SAUCE patches to improve the extra "low latency" requirements, but

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-26 Thread Andrea Righi
** Description changed: [Impact] Ubuntu provides the "lowlatency" kernel: a kernel optimized for applications that have special "low latency" requirements. Currently, this kernel does not include any specific UBUNTU SAUCE patches to improve the extra "low latency" requirements, but

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-26 Thread Andrea Righi
** Description changed: [Impact] Ubuntu provides the "lowlatency" kernel: a kernel optimized for applications that have special "low latency" requirements. Currently, this kernel does not include any specific UBUNTU SAUCE patches to improve the extra "low latency" requirements, but

[Kernel-packages] [Bug 2051342] Re: Enable lowlatency settings in the generic kernel

2024-01-26 Thread Andrea Righi
** Description changed: [Impact] Ubuntu provides the "lowlatency" kernel: a kernel optimized for applications that have special "low latency" requirements. Currently, this kernel does not include any specific UBUNTU SAUCE patches to improve the extra "low latency" requirements, but