Re: Problem with lttng-0.6.3 for MIPS arch

By the way,

If you want to split the commands like you do, you should start by creating the
lttctl trace, then start lttd, take a eventdefs snapshot, then start tracing,
stop it and destroy the channels. (that's what lttctl -d and lttctl -R do)

The one thing you do wrong here is to start lttd before the lttctl create and
to bind it on the LTT root directory before any trace is created.

Mathieu


* Sagar Borikar ([email protected]) wrote:
>   
> Hello,
> 
> I have ported lttng-0.6.3 on kernel 2.6.18 on MIPS target. I am facing problem while getting traces as "trace: no such file or directory." The NFS filesystme is mounted on target.
> 
> The procesure followed to start the ltt daemon and lttctl are:
> 
> #./lttd -t /tmp/trace -c /mnt/debugfs/ltt -d
> This runs ltt daemon in background successfully
> As it display the message 
> 
> "Linux Trace Toolkit Trace Daemon
> 
> Reading from debugfs directory : /mnt/debugfs/ltt/
> Writing to trace directory : /tmp/trace"
> 
> I am able to start the trace using following command
> 
> #./lttctl -n trace_name -s
> and the tracing starts as console message is 
> 
> controlling trace : trace_name
> 
> but when I try to stop the trace I get the following error:
> 
> #./lttctl -n trace_name -q
> 
> ltt_control : trace trace_name
> Linux Trace Toolkit Trace Control
> 
> Stop Trace Error: No Such File or Directory 
> 
> I could debug the lttctl by insertign some printfs. I added them in lttctl_stop function after lttctl_netlink_sendto and lttctl_netlink_recvfrom.  As mentioned below.
> 
> 476  err = lttctl_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len);
> 475     if(err < 0) goto senderr;
> 476
> 477     printf("Error after sendto %d\n",err);
> 478     err=0;
> 479     err = lttctl_netlink_recvfrom(h, (void*)&ack, sizeof(ack), 0);
> 480     if(err < 0) goto senderr;
> 481
> 482     printf("Error after recv %d\n",err);
> 483
> 484     err = ack.nlerr.error;
> 485     if(err != 0) {
> 486         errno = err;
> 487         lttctl_perror("Second  Stop Trace Error : Error Code");
> 488         printf("Second Received error code : %d\n",err);
> 489         return err;
> 490     }
> 
> 
> Then the message received was :
> 
> Error after sendto 560
> Error after recv 36
> Second  Stop Trace Error : Error Code: No such file or directory
> Second Received error code : 2
> 
> 
> Any inputs? 
> Am I missing any wrong steps?
> 
> Thanks and Best Regards,
> Sagar Borikar
> 
> 
> 
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