Thanks very much for your reply! I had followed the tutorial , but it doesn't work. 1. mlockall 2. echo -1 > /proc/sys/kernel/sched_rt_runtime_us 3. under linux 4.4.32 with rt patch I will be very glad if you can test this case yourself. Thanks ! On Sat, Feb 3, 2018 at 12:46 AM, Grygorii Strashko <grygorii.strashko@xxxxxx> wrote: > Hi > > You probably need to look at > https://wiki.linuxfoundation.org/realtime/documentation/howto/applications/start > https://rt.wiki.kernel.org/index.php/Main_Page > > it not enough to just set policy and prio - you need to follow some > additional rules while creating RT App. > > > > On 02/01/2018 09:52 PM, Journey Journey wrote: >> Hi Dear All >> >> I had tested a program in order to calculate computing time in a >> machine with 48 intel cpu cores. >> >> 1. when running ./test, it outputs like this: >> MM: 324.039000 ms >> MM: 324.052000 ms >> MM: 324.079000 ms >> MM: 324.042000 ms >> MM: 324.060000 ms >> MM: 324.052000 ms >> MM: 324.026000 ms >> MM: 324.040000 ms >> MM: 324.075000 ms >> MM: 324.011000 ms >> MM: 324.072000 ms >> >> 2. running other programs, like sample code 2 >> ./aa & >> ./aa & >> .... >> about 30 times >> >> 3. ./test output changes: >> MM: 354.601000 ms >> MM: 322.289000 ms >> MM: 322.250000 ms >> MM: 322.348000 ms >> MM: 354.700000 ms >> MM: 322.556000 ms >> MM: 354.834000 ms >> MM: 354.816000 ms >> MM: 354.777000 ms >> MM: 354.812000 ms >> MM: 322.451000 ms >> MM: 322.507000 ms >> MM: 322.473000 ms >> >> 4. For purpose to decrease computing cost time, I had tried: >> (1) set test policy to SCHED_RR/SCHED_FIFO, and priority to 50/98 >> chrt -f -p 98 5911 >> (2) bind test to specific cpu >> taskset -pc 4 5911 >> (3) limit aa processes to other cpus >> for i in `ps -ef |grep aa|awk '{print $2}'`; do echo $i; taskset -pc >> 5-47 $i; done >> >> It still not working, the result is not good. >> MM: 322.316000 ms >> MM: 322.307000 ms >> MM: 326.739000 ms >> MM: 354.399000 ms >> MM: 354.662000 ms >> MM: 354.740000 ms >> MM: 322.275000 ms >> >> 5. But when limit aa processes to a small cpuset, it works, >> for i in `ps -ef |grep aa|awk '{print $2}'`; do echo $i; taskset -pc >> 5-7 $i; done >> >> the result: >> MM: 322.304000 ms >> MM: 322.335000 ms >> MM: 322.344000 ms >> MM: 322.319000 ms >> MM: 322.340000 ms >> MM: 322.328000 ms >> MM: 322.298000 ms >> MM: 322.318000 ms >> >> >> It's quite amazing why such low priority processes can affect realtime >> process, please help me! >> >> >> >> Sample test code1: >> >> #include <stdio.h> >> #include <sys/time.h> >> >> void calc() { >> int c, d, k; >> int m = 100000, q = 1, p = 1000; >> int sum; >> for (c = 0; c < m; c++) { >> for (d = 0; d < q; d++) { >> for (k = 0; k < p; k++) { >> sum = c * m * d * q * p * k; >> } >> } >> >> } >> } >> >> int main() { >> struct timeval t1, t2; >> double elapsedTime; >> >> while(1) { >> gettimeofday(&t1, NULL); >> calc(); >> gettimeofday(&t2, NULL); >> elapsedTime = (t2.tv_sec - t1.tv_sec) * 1000.0; // sec to ms >> elapsedTime += (t2.tv_usec - t1.tv_usec) / 1000.0; // us to ms >> printf("MM: %lf ms\n", elapsedTime); >> sleep(1); >> } >> } >> >> >> Sample Code 2: >> >> #include <stdio.h> >> >> int main() { >> while(1) { >> } >> } >> >> Thanks~ >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > -- > regards, > -grygorii -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
