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| | Interrupt handler - Wikipedia, the free encyclopedia |
 | | Interrupt handlers have a multitude of functions, which vary based on the reason the interrupt was generated and the speed at which the Interrupt Handler completes its task. | | | In response to an interrupt, there is a context switch, and the code for the interrupt is loaded and executed. | | | These handlers are initiated by either hardware interrupts or interrupt instructions in software, and are used for servicing hardware devices and transitions between protected modes of operation such as system calls. |
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http://en.wikipedia.org/wiki/Interrupt_handler
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| | Timing for KADAK AMX RTOS |
| | Interrupt latency consists of the sum of two components: processor interrupt latency and software interrupt latency. | | | Within the AMX environment, KADAK uses the term interrupt latency to refer to the time taken from the leading edge of an external interrupt request signal to the processor to the fetch of the first interrupt service instruction by the processor. | | | Of equal importance to interrupt latency is what KADAK calls handler latency, the time from the processor's first response to an interrupt request signal through to the first useful instruction in the interrupt service procedure. |
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http://www.kadak.com/html/kdkp2609.htm
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| | RTC Magazine |
| | Rather than estimating worst-case interrupt latency by ignoring the amount of time for which interrupts might be disabled, a better approach is not to disable interrupts in the software in the first place. | | | This is generally longer than the interrupt latency, and is important in systems where the response to the external event must involve use of OS services that are only accessible from the task level, not from the ISR level. | | | Interrupt latency is defined as the elapsed time between the occurrence of an interrupt and the execution of the first instruction in the corresponding interrupt service routine (ISR). |
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http://www.rtcmagazine.com/home/printthis.php?id=100152
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| | Programmable Interrupt Controller - Wikipedia, the free encyclopedia |
| | A Programmable Interrupt Controller (PIC) is a device which allows priority levels to be assigned to its interrupt outputs. | | | The IMR specifies which interrupts are to be ignored and not acknowledged. | | | When the device has multiple interrupt outputs to assert, it will assert them in the order of their relative priority. |
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http://en.wikipedia.org/wiki/Programmable_Interrupt_Controller
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| | Audio I |
| | Interrupt latency is a fundamental measure of an operating system’s performance and is not a factor that is open to optimization. | | | Latency effects the overall responsiveness of a DAW’s user interface to input gestures as well the applicability of a DAW for live input monitoring. | | | The most important performance criterion of a DAW is latency, i.e., the delay between when the software changes a sound and when that change is actually heard. |
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http://www.cakewalk.com/DevXchange/audio_i.asp
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| | LWN: Realtime and interrupt latency |
| | Scheduling latency is important, but the harder end of the realtime spectrum also places a premium on interrupt latency: how long the system takes to respond to a hardware interrupt. | | | Disabling interrupts solves the immediate problem, but it can lead to increased interrupt latency. | | | One of that driver's devices raises an interrupt while the lock is held, and the interrupt handler runs on the same CPU. |
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http://lwn.net/Articles/139784
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| | [No title] |
| | Knowledge of the worst case interrupt latency of an executive aids the application designer in determining the maximum period of time between the generation of an interrupt and an interrupt handler responding to that interrupt. | | | All sources of hardware interrupts were disabled, although the interrupt level of the XXX allows all interrupts. | | | The interrupt vector and entry overhead time was generated on an BSP_FOR_TIMES benchmark platform using the Multiprocessing Communications registers to generate as the interrupt source. |
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http://www.rtems.com/onlinedocs/doc-current/info/c4x.info-2
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| | Making interrupt design firmware friendly |
| | The delay in handling an interrupt, called the interrupt latency, is generally measured from the occurrence of the interrupt until the firmware begins to handle the interrupt. | | | The scheme used by hardware designers to implement the interrupts in an embedded system can, however, have a big effect on the interrupt latency. | | | While the interrupt latency can be very quick from a firmware perspective, from the perspective of the hardware this delay is always an eternity. |
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http://www.us.design-reuse.com/articles/article4154.html
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| | LSU EE 4770 Lecture Notes |
| | Definitions: Latency [of an interrupt handler or daemon task to an event]: Time from event occurrence to start of its handler or daemon task. | | | Response time [of interrupt handler or daemon task to an event]: Time from event occurrence to response. | | | Run time [of interrupt handler or daemon task]: The time needed to run1 on an unloaded system. |
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http://www.ece.lsu.edu/ee4770/1997/lsli16.html
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| | Interrupt Latency in 80386EX Based System |
| | Interrupt Latency: The time that elapses before an interrupt request is serviced by the CPU (recognition of the interrupt by the CPU with an interrupt acknowledge cycle). | | | Interrupt Service routine: A simple NULL INTR (For USR case) is shown below with number of clock cycles it would take to execute, assuming a 0Wait state memory (Wc=0), if the code memory has wait state then that should be added appropriately. | | | Interrupt response time: Time that elapses between the occurrence of an interrupt and the execution of the first instruction of that Interrupt Service Routine (ISR) by the CPU. |
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http://www.intel.com/design/intarch/technote/2153.htm
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| | MontaVista Software - Platform to Innovate |
| | Generally the hardware part of the interrupt latency is trivial as compared to the software part, so we simply treat the software part of the interrupt latency as the entire interrupt latency. | | | Interrupt latency, kernel preemption latency and context switch latency are key benchmarks to demonstrate the real-time performance of Linux kernel. | | | Both hardware and software latencies contribute to interrupt latency. |
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http://www.mvista.com/products/realtime_benchmarks.html
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| | Interrupt Latency |
| | After the assertion of the interrupt input you’ll see a clear space – that’s the minimum system latency to this input. | | | Latency as defined by CPU vendors varies from zero (the processor is ready to handle an interrupt RIGHT NOW) to the max time specified. | | | Connect this bit to one input of an oscilloscope, tying the other input to the interrupt signal itself. |
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http://www.ganssle.com/articles/interruptlatency.htm
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| | FAQ: Is there any information available in Concept on interrupt latency time? |
| | Using a interval timer interrupt instruction adds about 6% to the scan time of the scheduled ladder logic, this increase does not include the time required to execute the interrupt handler subroutine associated with the interrupt. | | | The performance of interrupt related instructions is especially critical. | | | Yes, there is information available in Concept on interrupt latency time. |
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http://www.modicon.com/85256E74004E079B/all/C881DD7782EB5CA085256F0F00499234!OpenDocument
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| | iqexpand.com |
| | Interrupt latency is the guaranteed maximum response time of the system to an electronic event (e.g. | | | Thus, almost all general-purpose computing systems use "virtual memory" and also have unpredictable interrupt latencies. | | | Such a scheduler keeps critical pieces of code and data in solid-state RAM and guarantees a minimum amount of CPU time and a maximum interrupt latency. |
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http://computer_architecture.iqexpand.com
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| | ARM Technical Support FAQs - How does the interrupt handling latency of the ARM720T compare with ARM7TDMI? |
| | In both cases, when the interrupt is recognised, the core allows the current instruction to complete. | | | The code may be marked as cacheable and it may go in the cache, but is not immune from replacement after subsequent linefills. | | | In the 7TDMI case, the addresses being loaded might be in the slowest region of memory and so lots of wait states would be added by the memory system before the interrupt was handled. |
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http://www.arm.com/support/faqip/3710.html
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| | Stack Computers: 6.5 INTERRUPTS AND MULTI-TASKING |
| | If an interrupt is pending, the address of the streamed instruction is pushed onto the return stack as the address to be executed upon return from the interrupt, and the interrupt is allowed to be processed. | | | These interrupts do things such as add a few milliseconds to the time-of-day counter, or copy a byte from an input port to a memory buffer. | | | Another approach that is used by stack processors is to use a software restriction on the size of the repeat count allowed to be used with streaming instructions. |
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http://www.ece.cmu.edu/~koopman/stack_computers/sec6_5.html
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| | RTOS Selection Guide - real-time operating system, criteria, latency |
| | Given these characteristics and the relative priorities of the tasks and interrupts in your system, it is possible to analyze the worst-case performance of the software using a technique such as rate monotonic analysis. | | | These numbers may be different for different processors, but it is reasonable to expect that if the algorithm is deterministic on one processor it will be so on any other. | | | Finally, and only if interrupts are enabled, the CPU's context is saved and the ISR associated with the interrupt is started. |
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http://www.netrino.com/Articles/RTOSes
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| | kernel - real-time multitasking kernel, embedded realtime kernel |
| | Interrupts are re-enabled as soon as possible to minimize application latency. | | | For some people, the interrupt latency of a kernel is the time it takes before a task responds to an interrupt. | | | The input channel of the UART interrupts each time a character is received. |
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http://www.smxinfo.com/articles/lsr_art/lsr_art.htm
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| | OSR's ntdev List: ISR Latency question |
| | So, in my opinion, it is not hardware interrupt latency that is producing the large delays we always hear about, but rather Operating System issues, such as searching for the proper isr, TLB and the caches. | | | If you (heresy!) run your interrupt on a trap gate instead of on an interrupt gate, you are guaranteed that nobody's going to interrupt you, although of course you may still see your interrupt routine running concurrently on more than one processor. |
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http://www.osronline.com/showThread.cfm?link=21424
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| | Reducing Interrupt Latency |
| | The time it takes from that the external unit signals an interrupt to the time it’s handled by the software is called interrupt latency. | | | It is clear that the interrupt latency in a system can be shortened by locking parts of code into the cache. | | | The goal of the thesis project is to research if the cache could be used to reduce the interrupt latency in real life industrial systems and if so how. |
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http://www.e.kth.se/~e96_dbu/ex/description.html
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| | Reducing Interrupt Latency |
| | Since the entire interrupt handler of OSE is much smaller than 32 kb locking the entire L1 instruction cache is really overkill, but hey, at least now you can measure the interrupt latency on the MPC750 so that day wasn't a complete waste of time. | | | The results were pretty good, I didn't expect that the interrupt latency would decrease as much as it did after locking the interrupt handler into the cache. | | | I figured that I really don't need to measure the latency, it is sufficient to count the number of hits in the cache to see if locking has a positive or negative effect on the system. |
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http://www.e.kth.se/~e96_dbu/ex/journal.html
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| | Guide to Realtime Programming |
| | A system's interrupt service routine (ISR) latency is the elapsed time from when an interrupt occurs until execution of the first instruction in the interrupt service routine. | | | This can improve system realtime latency, because when the UBC has consumed its maximum allocation of memory for buffering file data, the least recently used buffers must be flushed to disk if they are modified. | | | When there are other ISRs of equal or greater interrupt priority level running at the time that the realtime device interrupts, the realtime device ISR is blocked from running until the current ISR is finished. |
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http://www.iso.port.ac.uk/docs/digital_unix_40D/APS33DTE/DOCU_012.HTM
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| | LWN: Read-copy-update and interrupt latency |
| | The interrupt handler then cannot immediately free up the element, since the interrupted mainline code might well still be referencing it. | | | That cleanup work is done with a software interrupt, meaning it can happen after a hardware interrupt or at rescheduling time. | | | For an example of why this is needed, consider an interrupt handler (perhaps softirq) that deletes an element from a data structure that can be referenced from mainline code. |
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http://lwn.net/Articles/65832
(716 words)
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| | Interrupt latency on 2810 - DSP |
| | to fill and the first interrupt instruction to execute. | | | A 1500 instruction cycle interrupt response time is a bit excessive on | | | Since the external interrupts are fetched after a minimum of 12*tXCO, if |
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http://www.castalk.com/ftopic6608.html
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| | TI C671x Interrupt latency and DSP BIOS |
| | I could do two things as a work around: I could use an NMI for this audio interrupt (by feeding NMI with a skewed version of Left/Right clock), or I could set up the EDMA to be completely autonomous and not require accurate interrupt events at all. | | | Any example of a minimal NMI interrupt would be helpful here. | | | I have not been able to prevent the NMI from crashing my system, and I assume that's because I can't use the dispatcher, so I have to write it in assembly language? |
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http://talkaboutelectronicequipment.com/group/comp.dsp/messages/155708.html
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| | Interrupt Latency - ASM vs. Basic - MELabs PICBASIC Forums |
| | Assembly language is still the fastest way to handle interrupt. | | | I'm keeping the main loop as simple as possible to avod delays in servicing the interrupt, and thus minimizing the chance of buffer overrun. | | | USART and interrupt latency - not a problem |
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http://www.picbasic.co.uk/forum/showthread.php?t=1056
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| | [No title] |
| | Interrupt routine for the network hardware will take 100 usec to do work How will the system respond? | | | Depends Set network int to a lower priority than micro interrupt and it will have no effect Set priority higher and the time taken by network int adds to int latency for the interprocessor interrupt and it runs past deadline ¡\ & Z I Z Z á Z & I á ªb _ | | | cannot meet 625 usec deadline ¡& " " ªP D ó à ¨ Worst case interrupt latency ¨l What if we add networking capability? |
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http://www.ntu.edu/secure/CourseResources/AC/SE746-NT/ppt/Lecture16.ppt
(156 words)
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| | about interrupt latency Linux Kernel |
| | You can't measure interrupt latency that way even | | | i'm trying to estimate the interrupt latency (time between hardware | | | > i'm trying to estimate the interrupt latency (time between hardware |
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http://www.gossamer-threads.com/lists/linux/kernel/522173
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| | USART and interrupt latency - not a problem - MELabs PICBASIC Forums |
| | I've been using USART and serial interrupts to receive 7 byte commands, as was very worried that the buffer might overflow before I could service the interrupt. | | | USART and interrupt latency - not a problem | | | I had a main loop that checked for incoming data and responded, using many IF statements. |
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http://www.picbasic.co.uk/forum/showthread.php?p=5202
(303 words)
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| | HI-TECH Software Forums: Interrupt latency |
| | I know nothing about interrupt latency problem, just heard about it. | | | I understand that the bootloader will add some extra latency, but how to be sure that is the problem? | | | The problem is not on the bootloader, I've check the bootloaded code by read it back with a programmer. |
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http://htsoft.com/forum/all/showthreaded.php/Cat/0/Number/13204/page/fpart
(187 words)
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| | Hexapedia - Microprogram |
| | Such variations in instruction length interfere with pipelining and interrupt latency. | | | Some CISC processors include instructions that can take a very long time to execute. |
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http://www.hexafind.com/encyclopedia/microcode
(1225 words)
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| | DSP Trick: Relaxed Autobuffer Interrupt Latency (For ADI Serial Ports) |
| | As the data comes in initially, the data will be written into even addresses in the autobuffer. | | | Application: When you need more than a one-sample latency before processing an interrupt from one of ADI's autobuffered serial ports. | | | Introduction: This trick actually came to me in a dream (I'm not making this up!) It might sound a bit wacky, but bear with me - I've thought it through during the daylight hours and it still makes sense. |
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http://www.dspguru.com/comp.dsp/tricks/micro/adi/relax.htm
(697 words)
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| | [mythtv] Maybe it *is* interrupt latency |
| | I think it's software latency in the kernel: something in the kernel is consuming CPU time in such a way that the bttv driver is being starved just enough to cause it to intermittently lose data from the hardware buffer. | | | Is there an easy way to tweak the timeslices given to individual processes? | | | I don't think it is a PCI latency issue: I doubt the bus is even 20% busy, so the chances of there being significant contention causing latency is pretty low. |
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http://www.mythtv.org/pipermail/mythtv-dev/2005-January/029950.html
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| | Gelato :: Community |
| | I've been trying to measure the interrupt latency from PCI bus to | | | I've been using a PCI device with a timer that can | | | interrupt on the PCI card is around 10 microseconds. |
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http://www.gelato.org/community/answer_threaded.php?id=1_529
(175 words)
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| | C51: LATENCY OF INTERRUPT SERVICE ROUTINES |
| | For example, the following all delay an interrupt: | | | Assuming that interrupts are enabled and that there is no higher priority interrupt that is executing, a new interrupt is serviced by the Microcontroller immediately. | | | There are a number of things that impact how quickly an interrupt is serviced. |
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http://www.keil.com/support/docs/1808.htm
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| | OSR's windbg List: Interrupt latency on debugee machine |
| | OSR's windbg List: Interrupt latency on debugee machine | | | While testing a synchronous communications driver on build 2195 free I noticed that I was missing some interrupts on the debugee machine. | | | Furthur investigation with a scope showed that when running the debugger the interrupt latency for my interrupt was approx 50 millisecs. |
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http://www.osronline.com/showThread.cfm?link=1068
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| | Streaming Media - Soflex Online |
| | Having enough CPU power and bus bandwidth to support the required data rates | | | Creating low-latency interrupt paths in the OS to prevent buffer underrun |
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http://www.soflexonline.com/articles/streaming-media.html
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