query...

query...

[raja]

   Hi,
      I am Creating a posix message queue using the following code.


#include <stdio.h>
#include <stdlib.h>
#include <mqueue.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>

int main(int argc,char *argv[])
{
    mqd_t mq_des;
    mq_des = mq_open(argv[1],O_CREAT | O_RDWR | O_EXCL,S_IRUSR | S_IWUSR 
| S_IRGRP | S_IROTH , NULL);
    if(mq_des < 0)
    {
        printf("Unable To Create MsgQ\n");
        perror("mq_open");
        return mq_des;
    }
    printf("MsgQ is Opened With Descriptor : %d\n",mq_des);
    return mq_des;
}


and I after compiling I am giving

./a.out /root/Desktop/msgq1


But It is giving as unable to create message queue and showing error as
'permission denied'

Would you please help me.

Re: query...

[Nikhil Dharashivkar]

I think it could be root permissions problem. Are you running this
binary as root user ?


On 8/9/05, raja <vnagaraju@effigent.net> wrote:
>    Hi,
>       I am Creating a posix message queue using the following code.
> 
> 
> #include <stdio.h>
> #include <stdlib.h>
> #include <mqueue.h>
> #include <errno.h>
> #include <string.h>
> #include <fcntl.h>
> #include <sys/stat.h>
> #include <sys/types.h>
> 
> int main(int argc,char *argv[])
> {
>     mqd_t mq_des;
>     mq_des = mq_open(argv[1],O_CREAT | O_RDWR | O_EXCL,S_IRUSR | S_IWUSR
> | S_IRGRP | S_IROTH , NULL);
>     if(mq_des < 0)
>     {
>         printf("Unable To Create MsgQ\n");
>         perror("mq_open");
>         return mq_des;
>     }
>     printf("MsgQ is Opened With Descriptor : %d\n",mq_des);
>     return mq_des;
> }
> 
> 
> and I after compiling I am giving
> 
> ./a.out /root/Desktop/msgq1
> 
> 
> But It is giving as unable to create message queue and showing error as
> 'permission denied'
> 
> Would you please help me.
> -
> 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/
> 


-- 
Thanks and Regards,
         Nikhil.

RE: query...

[Sudheer]

First -> you hit the wrong ML
Second -> The message queue exists and the permissions specified by
oflag are denied, or the message queue does not exist and permission to
create the message queue is denied


-----Original Message-----
From: linux-kernel-owner@vger.kernel.org
[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of raja
Sent: Tuesday, August 09, 2005 3:59 PM
To: linux-kernel@vger.kernel.org
Subject: query...

   Hi,
      I am Creating a posix message queue using the following code.


#include <stdio.h>
#include <stdlib.h>
#include <mqueue.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>

int main(int argc,char *argv[])
{
    mqd_t mq_des;
    mq_des = mq_open(argv[1],O_CREAT | O_RDWR | O_EXCL,S_IRUSR | S_IWUSR

| S_IRGRP | S_IROTH , NULL);
    if(mq_des < 0)
    {
        printf("Unable To Create MsgQ\n");
        perror("mq_open");
        return mq_des;
    }
    printf("MsgQ is Opened With Descriptor : %d\n",mq_des);
    return mq_des;
}


and I after compiling I am giving

./a.out /root/Desktop/msgq1


But It is giving as unable to create message queue and showing error as
'permission denied'

Would you please help me.
-
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/

query

[Filip, Anotonov]

Dear Sirs,

Our company is proud to offer new Business Directories from Russia, Eastern and Western-European countries.

Also we offer a database with contact details of Russian billionaires.

You can find detailed information about our products at our web site.

Sincerely,

Filip, Anotonov,
Zakmedia, Russia.

Query

[snmp snmp]

Hi ,
     Me and my friends are working on a new concept.
     Idea is to run different kernels on different cores in a
multicore architecture. Each kernel is performing logically different
tasks. We believe to improve the cache performance and reduce cpu idle
time. This concept can be applied to filers , graphics processing
systems , embedded systems.
     Our implementation is on Intel core 2 duo machine. So far our
implementation includes running two kernels simultaneously (one on
each core) , handling hard-disk on one core and ethernet on another
core so as to divide the network and disk subsystem.

     But here we are unable to measure the performance. Can u please
suggest any method to measure the performance in terms of throughput
and response time?

     Thank you.

Re: Query

[Alan Cox]

>      Me and my friends are working on a new concept.

It's not really new. Various systems have done this historically, and
folks including Larry McVoy have proposed that for large scalability you
might build a system out of multiple separate kernels one on each NUMA
node and which had interfaces to loan or share pages with one another by
bumping page counts and handling coherency.

Cool to see someone trying some of this in Linux

>      Our implementation is on Intel core 2 duo machine. So far our
> implementation includes running two kernels simultaneously (one on
> each core) , handling hard-disk on one core and ethernet on another
> core so as to divide the network and disk subsystem.
> 
>      But here we are unable to measure the performance. Can u please
> suggest any method to measure the performance in terms of throughput
> and response time?

There are a bunch of standard benchmarks you can use. A lot of the big
name ones need clusters of systems to do the loading but there are things
like dbench that are quite useful on single systems.

For some of the applications you are talking about I think dbench might
be a good start.


Alan

Re: Query

[snmp snmp]

Thanks a lot for replying and your suggestions.
Actually , we have implemented this on SMP architecture.
We are trying to measure the performance with the tool you have suggested.


On Wed, Mar 16, 2011 at 5:24 PM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>>      Me and my friends are working on a new concept.
>
> It's not really new. Various systems have done this historically, and
> folks including Larry McVoy have proposed that for large scalability you
> might build a system out of multiple separate kernels one on each NUMA
> node and which had interfaces to loan or share pages with one another by
> bumping page counts and handling coherency.
>
> Cool to see someone trying some of this in Linux
>
>>      Our implementation is on Intel core 2 duo machine. So far our
>> implementation includes running two kernels simultaneously (one on
>> each core) , handling hard-disk on one core and ethernet on another
>> core so as to divide the network and disk subsystem.
>>
>>      But here we are unable to measure the performance. Can u please
>> suggest any method to measure the performance in terms of throughput
>> and response time?
>
> There are a bunch of standard benchmarks you can use. A lot of the big
> name ones need clusters of systems to do the loading but there are things
> like dbench that are quite useful on single systems.
>
> For some of the applications you are talking about I think dbench might
> be a good start.
>
>
> Alan
>

query

[Chanchal Chawla]

Hi All,
  
    i'm writing a file system code, i've a query regarding that, i want you
to help me out if possible, 
  
    is it possible to get the absolute mount point of a device at run time
in that code ? if it is possible then how we can get it ?

    i'll be thankful.
   
Regards
Chanchal

Re: query

[Andreas Dilger]

Chanchal Chawla writes:
>     i'm writing a file system code, i've a query regarding that, i want you
> to help me out if possible, 
>   
>     is it possible to get the absolute mount point of a device at run time
> in that code ? if it is possible then how we can get it ?

It was possible in 2.2 with a minor hack.  I did it by passing mountpoint
dentry via sb->s_root to filesystem, and using d_path() to do the path
lookup inside the filesystem.  s_root is overwritten by the filesystem
to hold the new fs root dentry, so you need to get the path and store it
elsewhere before s_root is overwritten.

In 2.4 I was trying to get Al Viro to tell me the best way to do this, but
because it is _possible_ to mount a filesystem multiple times under 2.4 it
raises a question about which mountpoint you should use.  In 2.4 you need
to supply an additional vfsmnt parameter to d_path(), and I never did get
an answer out of Al as to how to get a vfsmnt inside the filesystem, even
if there is only one mount of the filesystem.

Cheers, Andreas
-- 
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert