Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755368Ab1FJKLm (ORCPT ); Fri, 10 Jun 2011 06:11:42 -0400 Received: from ccserver2.unican.es ([130.206.5.101]:38229 "EHLO ccserver2.unican.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753332Ab1FJKLl (ORCPT ); Fri, 10 Jun 2011 06:11:41 -0400 Message-ID: <4DF1EDF3.6030808@unican.es> Date: Fri, 10 Jun 2011 12:12:03 +0200 From: Monica Puig-Pey User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.17) Gecko/20110424 Thunderbird/3.1.10 MIME-Version: 1.0 To: CC: , , Subject: Re: Changing Kernel thread priorities References: <4DEA1BA9.7020303@unican.es><4DEA1F22.6000603@unican.es><4DEA255 B.2050503@unican.es><4DECBE44.2070803@unican.es> <4DECC0DF.8070209@unican.es> <4DED051A.6020702@compro.net> <4DEDE411.6010807@unican.es> <4DEDEBFF.10907@cfl.rr.com> <4DEDF366.6000706@cfl.rr.com> <4DEE6F4E.1030107@unican.es> <4DEE7415.8000606@compro.net> In-Reply-To: <4DEE7415.8000606@compro.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [193.144.198.131] X-imss-version: 2.054 X-imss-result: Passed X-imss-scanInfo: M:P L:E SM:0 X-imss-tmaseResult: TT:0 TS:0.0000 TC:00 TRN:0 TV:6.5.1024(18190.006) X-imss-scores: Clean:92.85834 C:2 M:3 S:5 R:5 X-imss-settings: Baseline:1 C:1 M:2 S:2 R:2 (0.0000 0.0000) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6438 Lines: 213 El 07/06/11 20:55, Mark Hounschell escribi?: > On 06/07/2011 02:34 PM, Monica Puig-Pey wrote: >> El 07/06/11 11:46, Mark Hounschell escribi?: >>> On 06/07/2011 05:14 AM, Mark Hounschell wrote: >>>> On 06/07/2011 04:40 AM, Monica Puig-Pey wrote: >>>>> El 06/06/11 18:49, Mark Hounschell escribi?: >>>>>> On 06/06/2011 07:58 AM, Monica Puig-Pey wrote: >>>>>>> El 06/06/11 13:54, Rolando Martins escribi?: >>>>>>>> Hi, >>>>>>>> I use the following: >>>>>>>> >>>>>>>> PIDs=$(ps -eLo pid,cls,rtprio,pri,nice,cmd | grep -i "irq" | awk '{ >>>>>>>> print $1; }' | xargs echo) >>>>>>>> for i in $PIDs >>>>>>>> do >>>>>>>> ret=$(chrt -f -p 99 $i) >>>>>>>> done >>>>>>>> >>>>>>>> This will change the kernel thread associated with an irq >>>>>>>> handler to >>>>>>>> RT FIFO prio 99. >>>>>>>> Just change the script to your specific interrupt. >>>>>>>> >>>>>>>> Hope it helps, >>>>>>>> Rolando >>>>>>>> >>>>>>>> On Mon, Jun 6, 2011 at 12:47 PM, Monica Puig-Pey >>>>>>>> wrote: >>>>>>>>> I am writing a driver which has one kernel thread associated with >>>>>>>>> it. >>>>>>>>> I want to change the priority of this thread, so that I can >>>>>>>>> specify the >>>>>>>>> order in which it is scheduled following an interrupt. >>>>>>>>> I'm using: >>>>>>>>> >>>>>>>>> sched_setscheduler(struct task_struct *, int, struct sched_param >>>>>>>>> *); >>>>>>>>> >>>>>>>>> but it doesn't work. I tried to change the priority from the >>>>>>>>> init_module, >>>>>>>>> and also from the Kernel Thread, but there is no way. >>>>>>>>> >>>>>>>>> Kernel version is 2.6.31-11-rt >>>>>>>>> >>>>>>>>> What do I call to change a kernel thread priority? >>>>>>>>> >>>>>>>>> Thanks you very much >>>>>>>>> >>>>>>>>> M?nica >>>>>>>>> >>>>>>>>> -- >>>>>>>>> To unsubscribe from this list: send the line "unsubscribe >>>>>>>>> linux-rt-users" in >>>>>>>>> the body of a message to majordomo@vger.kernel.org >>>>>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>>>>>>> >>>>>>> >>>>>>> I need to change the priority from inside the driver, when creating >>>>>>> the >>>>>>> kernel thread. >>>>>>> Your script is useful but it is done in user context, >>>>>>> Any other help please? >>>>>> >>>>>> What I do is record the PID of the thread in the driver, then >>>>>> create an >>>>>> IOCTL for your driver that user land can call that either returns the >>>>>> PID so you can do it in user land, or cause the IOCTL code to do >>>>>> it in >>>>>> the driver. >>>>>> >>>>>> The same can be done with the affinity of the IRQ if you record the >>>>>> IRQ >>>>>> number. >>>>>> >>>>>> Mark >>>>>> -- >>>>>> To unsubscribe from this list: send the line "unsubscribe >>>>>> linux-rt-users" in >>>>>> the body of a message to majordomo@vger.kernel.org >>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>>> >>>>> But I don't have de PID of my Kthread, I only have the task_struc * >>>>> that >>>>> gives me the function: >>>>> >>>>> struct task_struct *kthread_create(int (*threadfn)(void *data), >>>>> void *data, >>>>> const char namefmt[], ...) >>>>> >>>>> How could I get the PID, and which function should I use in the IOCTL >>>>> (kernel context) for changing its priority? >>>>> >>>> >>>> The PID can be obtained from within the interrupt handler its self via >>>> current->pid. >>>> Obviously an interrupt has to occur first but after one interrupt you >>>> have it. >>>> >>>> Actually I had forgot how I handled this. Where I change the RT >>>> priority >>>> and cpu affinity is in what used to be called the Bottom Half and the >>>> IOCTL >>>> referred to above simply tells the BH to do it and with what values. >>>> >>> >>> In interrupt handler code snippet: >>> >>> struct task_struct *TSK; >>> struct sched_param PARAM = {.sched_priority = MAX_RT_PRIO }; >>> >>> TSK = current; >>> >>> Code snippet from BH: >>> >>> if (((rtom_rtprio != 0) && >>> (rtom_rtprio != PARAM.sched_priority)) || >>> (my_rtom_rtprio[BOARD] != rtom_rtprio)) { >>> >>> PARAM.sched_priority = rtom_rtprio; >>> my_rtom_rtprio[COUNT] = rtom_rtprio; >>> sched_setscheduler(TSK, SCHED_FIFO, &PARAM); >>> >>> set_cpus_allowed(TSK, rtom_devices[BOARD].irq_cpu_mask); >>> rtom_devices[BOARD].irq_task_pid = TSK->pid; >>> } >>> >>> rtom_rtprio and irq_cpu_mask are set by userland via an IOCTL. An >>> interrupt must occur for this to happen and my BOARD never shares IRQs. >>> >>> Mark >>> >> >> Thanks, your idea seems to be very useful to me. I was doing it very >> similar, but I didn't use the "current" variable to know the >> task_struct *. >> >> I have tried your suggestion on an easy example, but it didn't work. >> Insmod returns through the kernel >> >> [11334.895499] kthread: Unknown symbol sched_setscheduler >> >> Code shown below: >> >> #include >> #include >> #include >> >> #include >> #include >> #include >> #include >> >> >> struct task_struct *ts; >> >> int thread(void *data) >> { >> struct task_struct *TSK; >> struct sched_param PARAM = {.sched_priority = MAX_RT_PRIO }; >> TSK = current; >> >> PARAM.sched_priority = 50; >> sched_setscheduler(TSK, SCHED_FIFO, &PARAM); // <-- unknown symbol?? >> >> while(1){ >> printk("Hi I am kernel thread!\n"); >> msleep(100); >> if (kthread_should_stop()) >> break; >> } >> return 0; >> } >> >> >> int init_module(void) >> { >> printk(KERN_INFO "init_module() called\n"); >> ts=kthread_run(thread,NULL,"kthread"); >> return 0; >> } >> >> void cleanup_module(void) >> { >> printk(KERN_INFO "cleanup_module() called\n"); >> kthread_stop(ts); >> } >> . >> > > In kernel/sched.c > > EXPORT_SYMBOL_GPL(sched_setscheduler); > > If your driver is not GPL, you can't use it. > > Mark I did it, it worked!!! thank you so much!!!!! :) -- __________________________________________________________________________________ M?nica Puig-Pey Gonz?lez E-mail: puigpeym@unican.es Grupo de Computadores y Tiempo Real, Departamento de Electr?nica y Computadores. Facultad de Ciencias - Universidad de Cantabria Av. de los Castros s/n. 39005 - Santander, Espa?a __________________________________________________________________________________ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/