search for: tickless

Greetings- I'm running some USB DAHDI hardware on a system with a tickless kernel. The audio quality is quite poor. Could the tickless kernel be to blame? If so, when recompiling a kernel that is *not* tickless, is there a recommended KERNEL_HZ value? IIRC, older kernels used to be 1000, but newer ones are 250. Thoughts? --Tim

Hello, I am trying to build a custom kernel 2.6.24 from ubuntu with xen dom0 support. Does Xen support a tickless system (CONFIG_TICK_ONESHOT=y) and the realtime features of this kernel (CONFIG_PREEMPT=Y instead of CONFIG_PREEMP_VOLUNTARY)? Everytime, I set these options while configuring the kernel, the two settings are not regarded during kernel compilation. I also tried to build the kernel 2.6.27 from...

Hello everyone, I''ve always wondered - would dom0 be better off with a tickless kernel or not? In other words, can someone explain which choice to make with regards to CONFIG_NO_HZ? -- Stay in touch, Mark van Dijk. ,-------------------------------- ----------------------------'' Mon Aug 06 15:40 UTC 2012 Today is Pungenday, the 72nd day of Confus...

Hi, tinc has a fixed timeout of 1 second for select() in the main loop. I think this could be improved. Do you think the following patch goes into the right direction ? I don't know whether pselect() is standard enough (works under "current" linux, however I don't know about the other arches). Maybe a config option is necessary. It's probably possible

...nder if there are any specific recommendations about schedulers and so forth for optimum performance. There are a few areas that raise questions in my mind and I wonder if anyone has any opinions/comments on which settings are most suitable for use with asterisk: SLAB Allocator (SLAB or SLUB?) Tickless System (?) Preemption model (?) IO Scheduler (Anticipatory, Deadline or CFQ?) Flat or Sparse Memory (?) Timer Frequency (100Hz .. 1000hz) Cheers Alan -- The way out is open! http://www.theopensourcerer.com

Hello guys, Did anyone noticed how green CentOS 6 is compared to the previous release? I've been running a couple of "CentOS 6" VMs (on our vSphere environment) for the last couple of weeks and noticed a BIG difference when it comes to CPU usage when the VM is completely idle. I would like to share what I've seen in our environment: PfSense 2.0 (FreeBSD) VM: 40 Mhz CentOS

.... Thanks. >> > > There are quite a few; primarily we simply cannot make lwIP > (lpxelinux.0) work without it. However, pxelinux.0 should not depend on > this. > Now, tickful timekeeping is wasteful, but this is a bootloader, and functionality is the main concern. The "tickless" version still depended on the BIOS tick. -hpa

..., you you notice with the same command that it is incrementing via 1000/ every second. The vlaue of HZ that is exposed to modules is still 1000, thus not breaking module ABI. This same change is already present in RHEL5.1 today. In recent Fedora's, this is unnecessary due to the advent of the tickless kernel (which is useful for other reasons, including reduced power consumption on laptops). It is likely that RHEL6 will also be based on a tickless kernel. -- Stephen J Smoogen. -- CSIRT/Linux System Administrator How far that little candle throws his beams! So shines a good deed in a naughty wo...

Is there any known issues when trying to run CentOS (x86 or x64) on a fresh install of vmware 4.1? Details as to why I am asking are here in the CentOS forums: https://www.centos.org/modules/newbb/viewtopic.php?viewmode=flat&order=DESC&topic_id=28521&forum=39 Thanks! -Drew -------------- next part -------------- An HTML attachment was scrubbed... URL:

...s a good result that the worst case benchmark has a degradation of only 1%. VMware expects that these hardware virtualization features will be ubiquitous by 2011. Apart from the performance benefit, VMI was important for Linux on VMware's platform, from timekeeping point of view, but with the tickless kernels and TSC improvements that were done for the mainline tree, we think VMI has outlived those requirements too. In light of these results and availability of such hardware, we have decided to stop supporting VMI in our future products. Given this new development, I wanted to discuss how shou...

...s a good result that the worst case benchmark has a degradation of only 1%. VMware expects that these hardware virtualization features will be ubiquitous by 2011. Apart from the performance benefit, VMI was important for Linux on VMware's platform, from timekeeping point of view, but with the tickless kernels and TSC improvements that were done for the mainline tree, we think VMI has outlived those requirements too. In light of these results and availability of such hardware, we have decided to stop supporting VMI in our future products. Given this new development, I wanted to discuss how shou...

...we simply cannot make lwIP > (lpxelinux.0) work without it. However, pxelinux.0 should not depend on > this. I'm finding most of the problems on lpxelinux.0 > >Now, tickful timekeeping is wasteful, but this is a bootloader, and >functionality is the main concern. The "tickless" version still >depended on the BIOS tick. > Not really, a virtual environment can easily emulate the BIOS_timer at 0x046C but it has problems emulating a "real" timer interrupt to be hooked... That's the real problem. Just testing I have replaced the timing functions...

Hello all, My machine is a dual xeon x5520 server with NUMA support. I have some question about xen dom0 kernel. Since xen hypervisor has provided vcpu schedule, do we need to compile the following feature in dom0 kernel? - Tickless System (Dynamic Ticks) - High Resolution Timer Support - AMD IOMMU support - SMT (Hyperthreading) scheduler support - Multi-core scheduler suppor - Numa Memory Allocation and Scheduler Support - ACPI (Advanced Configuration and Power Interface) Support Because domU doesn''...

Hi everyone, I would like to ask what the current status of FLR, or better of FLR emulation is in latest Xen and if we can expect better support in the future. I''m asking because with xl (latest build and traditional qemu, not upstream), I always had problems with rebooting domUs which have vga cards passed through to them, because appearently they don''t get reinitialized and

...up warning easily at manual vcpu hot-remove/plug, or when suspend cancel into old context. One point here is to cover both stolen and blocked time to compare with offline threshold. vcpu hotplug falls into ''stolen'' case, but it''s not enough. Considering xen time model is tickless at idle, it''s possible that big block time is requested which also inflames softlockup thread. Signed-off-by Kevin Tian <kevin.tian@intel.com> Thanks, Kevin _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource...

Before 6.X Syslinux used a "Tick-less" timekeeping approach implemented in /core/bios.inc 6.X now implements a "Tick-counting" strategy (timer interrupt) implemented in /core/timer.inc I think this change presents issues when Sysylinux runs on Virtual Machines emulating a BIOS environment as they cannot correctly emulate the timer interrupt; see VMware's pdf:

...US but our BeOS-compatible scripting interface can certainly be exposed to it. In that spirit a port of the xdg-utils has been started[3]. It is our hope both project can benefit from each other. On behalf of the Haiku team, Fran?ois Revol. ---- [1] on the kernel side we can cite: preemptive tickless kernel, module hierarchy, intelligent hierarchical devfs... on the gui level: UTF-8, mime-based file managment, indexing of file meta-data... [2] BeOS itself used the X11 /etc/rgb.txt for its native browser, NetPositive, to map color names to values. BeOS (and Haiku) also uses modeline-like st...

...e specs on the new install: Physical HW Cisco UCS Blade (UCSB-B200-M3) vMware ESXI 5.5 VM Guest 4 vCPU w/ 32G of RAM tuned for latency/jitter (sensitivity=high) and full cpu/memory reservations. VM OS Redhat EL7 kernel 3.10.0-327.13.1.el7.x86_64 with tickless disabled e.g nohz=off and 1000HZ. Asterisk 13.1-cert6 using the timerfd module. Regards Robert McGilvray SS&C GlobeOp Associate Director, IT Network Security GlobeOp Financial Services | 1565 Front Street | Yorktown Hts NY 10598 t: +1 (914)-293-3584 | f: +1 (914)-293-3510 rm...

Hi guys, As I mentioned in a previous email I''ve refactored ntp and released a 1.0.0 release candidate. There''s one outstanding "flaw" remaining that''s bothering me and I wanted to solicit opinions on the list. We currently maintain a template per distribution that is close to the stock distribution provided ntp configuration. This leads to massive

...as a timebase. Xen and VMI implement sched_clock() as counting unstolen time, so time stolen by the hypervisor won't cause the watchdog to bite. The second adds per-cpu enable flags for the watchdog timer. This allows the timer to be disabled when the CPU goes into a (potentially unbounded) tickless sleep. I know this conflicts with fix-bogus-softlockup-warning-with-sysrq-t.patch in -mm2. I think that patch incorrectly changes the behaviour of the softlockup watchdog, and a better solution is to temporarily disable the watchdog while doing something known to be cpu-consuming, like a long sys...