Re: [Xenomai-help] syslog safe?

[Philippe Gerum <rpm@xenomai.org>]

Kent Borg wrote:
> On Tue, Apr 25, 2006 at 07:52:48PM +0200, Philippe Gerum wrote:
> 
>>No problem using it, but it will trigger an automatic switch to 
>>secondary mode in order to issue the right Linux syscalls. The thread 
>>will switch back to primary automatically again as soon as a (usually 
>>blocking) Xenomai syscall is issued.
> 
> 
> And, looking at strace output, it appears that is a syslog() is too
> low a priority to be logged it doesn't make a system call and so will
> not drop us out of realtime.
> 
> 

Do not trust strace there, it heavily relies on other glibc services, 
like buffered I/O, which might issue syscalls under various conditions. 
For instance, internal mutex locking might cause a syscall to deal with 
any contended request, or malloc called indirectly might ask for 
extending the caller's data segment, and so on. Additionally, some 
syslog flags, like LOG_CONS, do cause file I/O.

-- 

Philippe.