May 29, 2017 · RHEL-6.3 Below errors in VM console: "NOHZ: local_softirq_pending 100' was logged." Red Hat Enterprise Linux 6 Issue Kernel logs a message 'NOHZ: local_softirq_pending 100' A system shows a message about 'local_softirq_pending 100' in the system logs. Resolution This is an informal message for debugging, not necessarily a bug.

Currently, the Linux kernel does not allow running soft irqs for more than MAX_SOFTIRQ_TIME or rescheduling for more than MAX_SOFTIRQ_RESTART consecutive times. Once these limits are reached a special kernel thread, ksoftirqd is wake-up and all of the rest of pending soft irqs will be run from the context of this kernel thread. Deferrable functions, kernel tasklets, and work queues Linux kernel version This discussion of tasklets and work queues uses the 2.6.27.14 version of the Linux kernel. Linux tends to be a Swiss Army knife of functionality, and deferring functionality is no different. Since kernel 2.3, softirqs have been available that implement a set of 32 statically defined bottom halves. Linux Kernel - NOHZ: local_softirq_pending 08 Oct 11, 2009 I’ll Do It Later: Softirqs, Tasklets, Bottom Halves, Task

Softirqs are determined statically at compile-time of the Linux kernel and the open_softirq function takes care of softirq initialization. The open_softirq function defined in the kernel/softirq.c: +. void open_softirq (int nr, void (*action) (struct softirq_action *)) { softirq_vec [nr].action = action; }

The open_softirq function may be already familiar to you if you have read the ninth part about the interrupts and interrupt handling in the Linux kernel. In short words, the open_softirq function defined in the kernel/softirq.c source code file and executes initialization of the deferred interrupt handler. Sep 20, 2012 · The good news is that linux 2.6.35 has introduced nice feature - RPS (Receive Packet Steering).The core of the feature is get_rps_cpu() from dev/net/core.c, which computes a hash from IP source and destination addresses of an incoming packet and determines a which CPU send the packet to based on the hash. netif_receive_skb() or netif_rx() which call the function puts the packet to appropriate

* The two things to balance is latency against fairness - * we want to handle softirqs as soon as possible, but they * should not be able to lock up the box. */ #define MAX_SOFTIRQ_TIME msecs_to_jiffies(2) #define MAX_SOFTIRQ_RESTART 10 #ifdef CONFIG_TRACE_IRQFLAGS /* * When we run softirqs from irq_exit() and thus on the hardirq stack we need

[RFC,1/2] softirq: Defer net rx/tx - Linux kernel On Thu, Jan 11, 2018 at 10:48 AM, Linus Torvalds wrote: > On Thu, Jan 11, 2018 at 8:32 AM, Peter Zijlstra wrote: The softirq code doesn't understand that the > networking code does billions of operations, Kernel error messsage - NOHZ: local_softirq_pending 100