include/linux/interrupt.h lists the different softirqs. A very important softirq is the timer softirq (include/linux/timer.h): you can register to have it call functions for you in a given length of time. Softirqs are often a pain to deal with, since the same softirq will run simultaneously on more than one CPU.

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 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

Software Interrupt Context: Bottom Halves, Tasklets, softirqs. Whenever a system call is about to return to userspace, or a hardware interrupt handler exits, any `software interrupts' which are marked pending (usually by hardware interrupts) are run (kernel/softirq.c).Much of the …

Jun 11, 2010 · t1 runs softirq disabled code on CPU#0 interrupt happens, softirq is raised, but deferred (softirqs disabled) t1 calls cond_resched_softirq() enables softirqs via _local_bh_enable() calls schedule() t2 runs t1 is migrated to CPU#1 t2 is done and invokes idle() NOHZ detects the pending softirq ===== =====--- linux.orig/kernel/sched.c +++ linux While studying Linux interrupt handling I found that Tasklets and SoftIRQs are two different methods of performing "bottom half" (lesser priority work). I understand this (quite genuine need). Difference being, SoftIRQs are re-entarant while a Tasklet is NOT. That same SoftIRQ can run on different CPUs while this is NOT the case with Tasklets. /proc/softirq is softirq stats. Is /proc/interrupt both hard and soft interrupts or hard only?. I want to measure the rate of hard and soft irq's per second roughly using watch -n 1 grep 'foo' /proc/softirq and watch -n 1 grep 'bar' /proc/interrupt so I can compare the rate of hardware interrupt increase to software interrupt.

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Oct 11, 2016 · Linux 4.1.18-rt17-00028-g8da2a20 (vpc23) 06/04/16 _armv7l_(2 CPU) CPU HI/s TIMER/s NET_TX/s NET_RX/s BLOCK/s TASKLET/s SCHED/s HRTIMER/s RCU/s 0 0.00 999.72 0.18 9.54 0.00 89.29 191.69 261.06 0.00 Links to popular distribution download pages. Below you'll find links that lead directly to the download page of 25 popular Linux distributions.