Creating a pthread with a high priority

[fsivada]

(Updated...)

I'm trying to simply raise the priority of one thread.

My program has two threads:
1. a thread to capture from a UDP socket and write to the shared buffer
2. a thread to read from the shared buffer, parse the data and write to disk.

I'm using pthreads (POSIX threads).

All I want to do now is raise the priority of thread #1 as high as possible so it is unlikely (ideally impossible) for it to miss UDP packets.

To attempt to change thread priority I do:

pthread_setschedparam(pthread_udp_capture_process // Target thread
policy, // == 0. Same as thread had initially.
&sparam);

If I set sparam.schedpriority to anything other than 0 (the value schedpriority had when the thread was created), pthread_setschedparam returns the error: Invalid Argument.

I've tried sudo on my program. Still can't change the thread priority.

Does nice do it? Other recommended API?

Any ideas?

[nayyar]

hi
We had a similar problem to urs...
By default the sched policy is sched_other, and this has a static priority of 0.
so i tried changing the policy to sched_rr, and sched_fifo, in these u can set the priority to a higher value.... but not to a value <0.

So, what we did was that we ran our process on a lesser priority value. For eg is process name is abc, we ran
./nice -n 2 abc

This shall run the process abc in the priority of 2.

Now inside the thread (in which u want to raise the priority, the udp thread), set teh scheduling policy to Sched_rr and set its priority to 0.

This ways u can increase the priority level.

[anand_dk1]

you can raise the priority by running as root or check capabilities property of the system (CAPS_SYS_NICE).