Can't set the schedual parameter of threads in linux

Can't set the schedual parameter of threads in linux

[yang]

Hello,
    I encounter a problem when I transplant application.
    There is no effect to the pthread when I call pthread_setschedparam() function in test program,  and it's policy and priority are stilll zero, not what I expected, after call pthread_getschedparam(). The codes  is as the follow:

#include <sched.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <linux/ipc.h>
#include <linux/msg.h>
#include <errno.h>
#include <stddef.h>
#include <string.h>

void * func()
{
        while (1);
    return;
}

int main()
{
    pthread_attr_t tattr;
    pthread_t tid;
    int policy;
    int ret;
    int newprio = 20;
    struct sched_param param;

    ret = pthread_attr_init (&tattr);
    if (ret != 0)
    {
        printf("Error in init: %s\n", strerror(errno));
    }

    ret = pthread_attr_getschedparam (&tattr, &param);
    if (ret != 0)
    {
        printf("Error in get after init: %s\n", strerror(errno));
    }
    ret = pthread_attr_setdetachstate(&tattr, PTHREAD_CREATE_DETACHED);
   if (ret != 0)
    {
        printf("Error in setdea: %s\n", strerror(errno));
    }
    ret = pthread_attr_setschedpolicy(&tattr, SCHED_RR);
    if (ret != 0)
    {
        printf("Error in setpolicy: %s\n", strerror(errno));
    }

    param.sched_priority = newprio;
    ret = pthread_attr_setschedparam (&tattr, &param);
    if (ret != 0)
    {
        printf("Error in set: %s\n", strerror(errno));
    }

    ret = pthread_create (&tid, &tattr, (int*) func, NULL);
    if (ret != 0)
    {
        printf("Error in create: %s\n", strerror(errno));
    }

    param.sched_priority = -1;
    ret = pthread_getschedparam (tid, &policy, &param);
    if (ret != 0)
    {
        printf("Error in get after create: %d %s\n", ret, strerror(errno));
    }

    printf("policy: %d\tpriority: %d\n", policy, param.sched_priority);

    return 0;

}

    The output is :
    policy: 0    priority: 0

    Would you like to tell me how to set the policy and priority to pthreads in Red Hat.? Thank you very much!
    Best regards,
                                     yang


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: Can't set the schedual parameter of threads in linux

[Jaap-Jan Boor]

yang,

Are you running your application as root? Also, try to get/set
the pthread schedule parameters in the pthread context itself.

Jaap-Jan

On Mar 11, 2004, at 2:06, yang wrote:

>
> Hello,
>     I encounter a problem when I transplant application.
>     There is no effect to the pthread when I call
> pthread_setschedparam() function in test program,  and it's policy and
> priority are stilll zero, not what I expected, after call
> pthread_getschedparam(). The codes  is as the follow:
>
> #include <sched.h>
> #include <pthread.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <sys/types.h>
> #include <linux/ipc.h>
> #include <linux/msg.h>
> #include <errno.h>
> #include <stddef.h>
> #include <string.h>
>
> void * func()
> {
>         while (1);
>     return;
> }
>
> int main()
> {
>     pthread_attr_t tattr;
>     pthread_t tid;
>     int policy;
>     int ret;
>     int newprio = 20;
>     struct sched_param param;
>
>     ret = pthread_attr_init (&tattr);
>     if (ret != 0)
>     {
>         printf("Error in init: %s\n", strerror(errno));
>     }
>
>     ret = pthread_attr_getschedparam (&tattr, &param);
>     if (ret != 0)
>     {
>         printf("Error in get after init: %s\n", strerror(errno));
>     }
>     ret = pthread_attr_setdetachstate(&tattr, PTHREAD_CREATE_DETACHED);
>    if (ret != 0)
>     {
>         printf("Error in setdea: %s\n", strerror(errno));
>     }
>     ret = pthread_attr_setschedpolicy(&tattr, SCHED_RR);
>     if (ret != 0)
>     {
>         printf("Error in setpolicy: %s\n", strerror(errno));
>     }
>
>     param.sched_priority = newprio;
>     ret = pthread_attr_setschedparam (&tattr, &param);
>     if (ret != 0)
>     {
>         printf("Error in set: %s\n", strerror(errno));
>     }
>
>     ret = pthread_create (&tid, &tattr, (int*) func, NULL);
>     if (ret != 0)
>     {
>         printf("Error in create: %s\n", strerror(errno));
>     }
>
>     param.sched_priority = -1;
>     ret = pthread_getschedparam (tid, &policy, &param);
>     if (ret != 0)
>     {
>         printf("Error in get after create: %d %s\n", ret,
> strerror(errno));
>     }
>
>     printf("policy: %d\tpriority: %d\n", policy, param.sched_priority);
>
>     return 0;
>
> }
>
>     The output is :
>     policy: 0    priority: 0
>
>     Would you like to tell me how to set the policy and priority to
> pthreads in Red Hat.? Thank you very much!
>     Best regards,
>                                      yang
>
>


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: Can't set the schedual parameter of threads in linux

[Jaap-Jan Boor]

Yang,

You are right, I don't use the pthread_[gs]etschedparam() functions.
I use in the new thread's context the
pthread_attr_getschedpolicy(&tattr, &policy);
pthread_attr_getschedparam(&tattr, &param);

functions, and then set the new priority

param.sched_priority = newpriority;
pthread_setschedparam(pthread_self(), policy, &param);

Jaap-Jan

On Mar 11, 2004, at 14:10, yang wrote:

> Hi,
>        I did run my program as root, and the key to my problem is why
> it works well in Solaris system but not in Red Hat system.
>        Please copy the follow codes and run it in your system if you
> are spare and will. Thank you very much!
>        Best regards,
>                                                  yang
>
>
>> yang,
>>
>> Are you running your application as root? Also, try to get/set
>> the pthread schedule parameters in the pthread context itself.
>>
>> Jaap-Jan
>>
>> On Mar 11, 2004, at 2:06, yang wrote:
>>
>>>
>>> Hello,
>>>     I encounter a problem when I transplant application.
>>>     There is no effect to the pthread when I call
>>> pthread_setschedparam() function in test program,  and it's policy
>>> and
>>> priority are stilll zero, not what I expected, after call
>>> pthread_getschedparam(). The codes  is as the follow:
>>>
>>> #include <sched.h>
>>> #include <pthread.h>
>>> #include <stdio.h>
>>> #include <stdlib.h>
>>> #include <sys/types.h>
>>> #include <linux/ipc.h>
>>> #include <linux/msg.h>
>>> #include <errno.h>
>>> #include <stddef.h>
>>> #include <string.h>
>>>
>>> void * func()
>>> {
>>>         while (1);
>>>     return;
>>> }
>>>
>>> int main()
>>> {
>>>     pthread_attr_t tattr;
>>>     pthread_t tid;
>>>     int policy;
>>>     int ret;
>>>     int newprio = 20;
>>>     struct sched_param param;
>>>
>>>     ret = pthread_attr_init (&tattr);
>>>     if (ret != 0)
>>>     {
>>>         printf("Error in init: %s\n", strerror(errno));
>>>     }
>>>
>>>     ret = pthread_attr_getschedparam (&tattr, &param);
>>>     if (ret != 0)
>>>     {
>>>         printf("Error in get after init: %s\n", strerror(errno));
>>>     }
>>>     ret = pthread_attr_setdetachstate(&tattr,
>>> PTHREAD_CREATE_DETACHED);
>>>    if (ret != 0)
>>>     {
>>>         printf("Error in setdea: %s\n", strerror(errno));
>>>     }
>>>     ret = pthread_attr_setschedpolicy(&tattr, SCHED_RR);
>>>     if (ret != 0)
>>>     {
>>>         printf("Error in setpolicy: %s\n", strerror(errno));
>>>     }
>>>
>>>     param.sched_priority = newprio;
>>>     ret = pthread_attr_setschedparam (&tattr, &param);
>>>     if (ret != 0)
>>>     {
>>>         printf("Error in set: %s\n", strerror(errno));
>>>     }
>>>
>>>     ret = pthread_create (&tid, &tattr, (int*) func, NULL);
>>>     if (ret != 0)
>>>     {
>>>         printf("Error in create: %s\n", strerror(errno));
>>>     }
>>>
>>>     param.sched_priority = -1;
>>>     ret = pthread_getschedparam (tid, &policy, &param);
>>>     if (ret != 0)
>>>     {
>>>         printf("Error in get after create: %d %s\n", ret,
>>> strerror(errno));
>>>     }
>>>
>>>     printf("policy: %d\tpriority: %d\n", policy,
>>> param.sched_priority);
>>>
>>>     return 0;
>>>
>>> }
>>>
>>>     The output is :
>>>     policy: 0    priority: 0
>>>
>>>     Would you like to tell me how to set the policy and priority to
>>> pthreads in Red Hat.? Thank you very much!
>>>     Best regards,
>>>                                      yang
>>>
>>>
>>
>>
>>


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: Can't set the schedual parameter of threads in linux

[Mark Hatle]

I'm far from an expert on pthreads..  but these sound like things that
require "nptl".  And as far as I know, nptl isn't exactly ready for the
ppc-embedded space.. :|

--Mark

Jaap-Jan Boor wrote:
>
> Yang,
>
> You are right, I don't use the pthread_[gs]etschedparam() functions.
> I use in the new thread's context the
> pthread_attr_getschedpolicy(&tattr, &policy);
> pthread_attr_getschedparam(&tattr, &param);
>
> functions, and then set the new priority
>
> param.sched_priority = newpriority;
> pthread_setschedparam(pthread_self(), policy, &param);
>
> Jaap-Jan
>
> On Mar 11, 2004, at 14:10, yang wrote:
>
>> Hi,
>>        I did run my program as root, and the key to my problem is why
>> it works well in Solaris system but not in Red Hat system.
>>        Please copy the follow codes and run it in your system if you
>> are spare and will. Thank you very much!
>>        Best regards,
>>                                                  yang
>>
>>
>>> yang,
>>>
>>> Are you running your application as root? Also, try to get/set
>>> the pthread schedule parameters in the pthread context itself.
>>>
>>> Jaap-Jan
>>>
>>> On Mar 11, 2004, at 2:06, yang wrote:
>>>
>>>>
>>>> Hello,
>>>>     I encounter a problem when I transplant application.
>>>>     There is no effect to the pthread when I call
>>>> pthread_setschedparam() function in test program,  and it's policy
>>>> and
>>>> priority are stilll zero, not what I expected, after call
>>>> pthread_getschedparam(). The codes  is as the follow:
>>>>
>>>> #include <sched.h>
>>>> #include <pthread.h>
>>>> #include <stdio.h>
>>>> #include <stdlib.h>
>>>> #include <sys/types.h>
>>>> #include <linux/ipc.h>
>>>> #include <linux/msg.h>
>>>> #include <errno.h>
>>>> #include <stddef.h>
>>>> #include <string.h>
>>>>
>>>> void * func()
>>>> {
>>>>         while (1);
>>>>     return;
>>>> }
>>>>
>>>> int main()
>>>> {
>>>>     pthread_attr_t tattr;
>>>>     pthread_t tid;
>>>>     int policy;
>>>>     int ret;
>>>>     int newprio = 20;
>>>>     struct sched_param param;
>>>>
>>>>     ret = pthread_attr_init (&tattr);
>>>>     if (ret != 0)
>>>>     {
>>>>         printf("Error in init: %s\n", strerror(errno));
>>>>     }
>>>>
>>>>     ret = pthread_attr_getschedparam (&tattr, &param);
>>>>     if (ret != 0)
>>>>     {
>>>>         printf("Error in get after init: %s\n", strerror(errno));
>>>>     }
>>>>     ret = pthread_attr_setdetachstate(&tattr,
>>>> PTHREAD_CREATE_DETACHED);
>>>>    if (ret != 0)
>>>>     {
>>>>         printf("Error in setdea: %s\n", strerror(errno));
>>>>     }
>>>>     ret = pthread_attr_setschedpolicy(&tattr, SCHED_RR);
>>>>     if (ret != 0)
>>>>     {
>>>>         printf("Error in setpolicy: %s\n", strerror(errno));
>>>>     }
>>>>
>>>>     param.sched_priority = newprio;
>>>>     ret = pthread_attr_setschedparam (&tattr, &param);
>>>>     if (ret != 0)
>>>>     {
>>>>         printf("Error in set: %s\n", strerror(errno));
>>>>     }
>>>>
>>>>     ret = pthread_create (&tid, &tattr, (int*) func, NULL);
>>>>     if (ret != 0)
>>>>     {
>>>>         printf("Error in create: %s\n", strerror(errno));
>>>>     }
>>>>
>>>>     param.sched_priority = -1;
>>>>     ret = pthread_getschedparam (tid, &policy, &param);
>>>>     if (ret != 0)
>>>>     {
>>>>         printf("Error in get after create: %d %s\n", ret,
>>>> strerror(errno));
>>>>     }
>>>>
>>>>     printf("policy: %d\tpriority: %d\n", policy,
>>>> param.sched_priority);
>>>>
>>>>     return 0;
>>>>
>>>> }
>>>>
>>>>     The output is :
>>>>     policy: 0    priority: 0
>>>>
>>>>     Would you like to tell me how to set the policy and priority to
>>>> pthreads in Red Hat.? Thank you very much!
>>>>     Best regards,
>>>>                                      yang
>>>>
>>>>
>>>
>>>
>>>
>
>
>
>


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

RE: Can't set the schedual parameter of threads in linux

[Jean-Denis Boyer]

Your program logic is absolutely correct.
I ran it in my embedded PPC environment (as root) and got the following results:

policy: 2       priority: 20

The problem is elsewhere...

--------------------------------------------
 Jean-Denis Boyer, Eng.
 M5T Centre d'Excellence en Télécoms Inc.
 4283 Garlock Street
 Sherbrooke (Québec)
 J1L 2C8  CANADA
 (819)829-3972 x241
--------------------------------------------
> -----Original Message-----
> From: owner-linuxppc-embedded@lists.linuxppc.org
> [mailto:owner-linuxppc-embedded@lists.linuxppc.org]On Behalf Of yang
> Sent: 10 mars, 2004 20:07
> To: linuxppc-embedded@lists.linuxppc.org
> Subject: Can't set the schedual parameter of threads in linux
>
>
>
> Hello,
>     I encounter a problem when I transplant application.
>     There is no effect to the pthread when I call
> pthread_setschedparam() function in test program,  and it's
> policy and priority are stilll zero, not what I expected,
> after call pthread_getschedparam(). The codes  is as the follow:
>
> #include <sched.h>
> #include <pthread.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <sys/types.h>
> #include <linux/ipc.h>
> #include <linux/msg.h>
> #include <errno.h>
> #include <stddef.h>
> #include <string.h>
>
> void * func()
> {
>         while (1);
>     return;
> }
>
> int main()
> {
>     pthread_attr_t tattr;
>     pthread_t tid;
>     int policy;
>     int ret;
>     int newprio = 20;
>     struct sched_param param;
>
>     ret = pthread_attr_init (&tattr);
>     if (ret != 0)
>     {
>         printf("Error in init: %s\n", strerror(errno));
>     }
>
>     ret = pthread_attr_getschedparam (&tattr, &param);
>     if (ret != 0)
>     {
>         printf("Error in get after init: %s\n", strerror(errno));
>     }
>     ret = pthread_attr_setdetachstate(&tattr,
> PTHREAD_CREATE_DETACHED);
>    if (ret != 0)
>     {
>         printf("Error in setdea: %s\n", strerror(errno));
>     }
>     ret = pthread_attr_setschedpolicy(&tattr, SCHED_RR);
>     if (ret != 0)
>     {
>         printf("Error in setpolicy: %s\n", strerror(errno));
>     }
>
>     param.sched_priority = newprio;
>     ret = pthread_attr_setschedparam (&tattr, &param);
>     if (ret != 0)
>     {
>         printf("Error in set: %s\n", strerror(errno));
>     }
>
>     ret = pthread_create (&tid, &tattr, (int*) func, NULL);
>     if (ret != 0)
>     {
>         printf("Error in create: %s\n", strerror(errno));
>     }
>
>     param.sched_priority = -1;
>     ret = pthread_getschedparam (tid, &policy, &param);
>     if (ret != 0)
>     {
>         printf("Error in get after create: %d %s\n", ret,
> strerror(errno));
>     }
>
>     printf("policy: %d\tpriority: %d\n", policy,
> param.sched_priority);
>
>     return 0;
>
> }
>
>     The output is :
>     policy: 0    priority: 0
>
>     Would you like to tell me how to set the policy and
> priority to pthreads in Red Hat.? Thank you very much!
>     Best regards,
>                                      yang
>
>


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

RE: Can't set the schedual parameter of threads in linux

[Jaap-Jan Boor]

On Thu, 11 Mar 2004, Jean-Denis Boyer wrote:

>
> Your program logic is absolutely correct.
> I ran it in my embedded PPC environment (as root) and got the following results:
>
> policy: 2       priority: 20
>
> The problem is elsewhere...

RedHat 9 uses ntpl, that is a difference.

>
> --------------------------------------------
>  Jean-Denis Boyer, Eng.
>  M5T Centre d'Excellence en Télécoms Inc.
>  4283 Garlock Street
>  Sherbrooke (Québec)
>  J1L 2C8  CANADA
>  (819)829-3972 x241
> --------------------------------------------
> > -----Original Message-----
> > From: owner-linuxppc-embedded@lists.linuxppc.org
> > [mailto:owner-linuxppc-embedded@lists.linuxppc.org]On Behalf Of yang
> > Sent: 10 mars, 2004 20:07
> > To: linuxppc-embedded@lists.linuxppc.org
> > Subject: Can't set the schedual parameter of threads in linux
> >
> >
> >
> > Hello,
> >     I encounter a problem when I transplant application.
> >     There is no effect to the pthread when I call
> > pthread_setschedparam() function in test program,  and it's
> > policy and priority are stilll zero, not what I expected,
> > after call pthread_getschedparam(). The codes  is as the follow:
> >
> > #include <sched.h>
> > #include <pthread.h>
> > #include <stdio.h>
> > #include <stdlib.h>
> > #include <sys/types.h>
> > #include <linux/ipc.h>
> > #include <linux/msg.h>
> > #include <errno.h>
> > #include <stddef.h>
> > #include <string.h>
> >
> > void * func()
> > {
> >         while (1);
> >     return;
> > }
> >
> > int main()
> > {
> >     pthread_attr_t tattr;
> >     pthread_t tid;
> >     int policy;
> >     int ret;
> >     int newprio = 20;
> >     struct sched_param param;
> >
> >     ret = pthread_attr_init (&tattr);
> >     if (ret != 0)
> >     {
> >         printf("Error in init: %s\n", strerror(errno));
> >     }
> >
> >     ret = pthread_attr_getschedparam (&tattr, &param);
> >     if (ret != 0)
> >     {
> >         printf("Error in get after init: %s\n", strerror(errno));
> >     }
> >     ret = pthread_attr_setdetachstate(&tattr,
> > PTHREAD_CREATE_DETACHED);
> >    if (ret != 0)
> >     {
> >         printf("Error in setdea: %s\n", strerror(errno));
> >     }
> >     ret = pthread_attr_setschedpolicy(&tattr, SCHED_RR);
> >     if (ret != 0)
> >     {
> >         printf("Error in setpolicy: %s\n", strerror(errno));
> >     }
> >
> >     param.sched_priority = newprio;
> >     ret = pthread_attr_setschedparam (&tattr, &param);
> >     if (ret != 0)
> >     {
> >         printf("Error in set: %s\n", strerror(errno));
> >     }
> >
> >     ret = pthread_create (&tid, &tattr, (int*) func, NULL);
> >     if (ret != 0)
> >     {
> >         printf("Error in create: %s\n", strerror(errno));
> >     }
> >
> >     param.sched_priority = -1;
> >     ret = pthread_getschedparam (tid, &policy, &param);
> >     if (ret != 0)
> >     {
> >         printf("Error in get after create: %d %s\n", ret,
> > strerror(errno));
> >     }
> >
> >     printf("policy: %d\tpriority: %d\n", policy,
> > param.sched_priority);
> >
> >     return 0;
> >
> > }
> >
> >     The output is :
> >     policy: 0    priority: 0
> >
> >     Would you like to tell me how to set the policy and
> > priority to pthreads in Red Hat.? Thank you very much!
> >     Best regards,
> >                                      yang
> >
> >
>
>
>

--
J.G.J. Boor			  Anton Philipsweg 1
Software Engineer		  1223 KZ Hilversum
AimSys bv              		  tel. +31 35 689 1941
Postbus 2194, 1200 CD Hilversum   mailto:jjboor@aimsys.nl


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

RE: Can't set the schedual parameter of threads in linux

[erik.teose]

>> Your program logic is absolutely correct.
>> I ran it in my embedded PPC environment (as root) and got
>the following results:
>>
>> policy: 2       priority: 20
>>
>> The problem is elsewhere...
>
>RedHat 9 uses nptl, that is a difference.

And a big difference it is. Here's some bits of an email
conversation I recently had on this issue:

  >>RH9 introduces 'nptl', (locally known as 'non-portable threads
  >>library'), which is strictly SCHED_OTHER.  Any
  >>RTOS code which relies on prioritized scheduling to work reliably
  >>(including some of the v2pthreads emulation layer) will be broken with
  >>'nptl'....
  >>
  >Isn't 'nptl' also 'standard' in the new 2.6 kernel? Is it strictly
  >SCHED_OTHER in 2.6 also? Isn't that a severe blow to 'real-time'
  >embedded Linux? I don't understand...
  >
  Both statements are regrettably true. The developer(s) of 'nptl'
  regard regard real-time scheduling as 'nonsense' (that's what Ulrich
  Drepper called it!) and have no intentions of supporting it.
  Furthermore, their development priority is on scheduling efficiency
  rather than priority, and they believe it's okay to 'water down' the
  expectations of the applications programmer in order to boost
  performance.  Consequently I intend to personally take a look at their
  code to see what can be done to make it more desirable for the real-time
  applications community.  Drepper and crew don't see the shortcomings in
  their approach, so we in the real-time community will have to make any
  corrections ourselves.

So there we have it. The new 'nptl' threading library does not support
real-time scheduling. Comments?

Erik Teose
erik.teose@tek.com

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/