Re: [Adeos-main] [PATCH] tracer: use per-cpu trace buffers

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

Jan Kiszka wrote:
 > Gilles Chanteperdrix wrote:
 > > Jan Kiszka wrote:
 > >  > This patch addresses two issues:
 > >  > 
 > >  >  - fixes boot hang with CONFIG_IPIPE_TRACE, !CONFIG_IPIPE_TRACE_VMALLOC,
 > >  >    and large CONFIG_NR_CPUS (due to the huge trace buffers this implies,
 > >  >    even if the system has only a few CPUs in fact)
 > > 
 > > This is something I observed even on UP systems: the kernel does not
 > > boot on ARM if CONFIG_IPIPE_TRACE_VMALLOC is not selected.
 > > 
 > 
 > Yeah, well known, that's why we have vmalloc'ed trace buffers.
 > 
 > I just wondered again if this is an arch-specific issue, or if it
 > depends on the RAM size. If it is arch-specific, you are welcome to
 > change the default of IPIPE_TRACE_VMALLOC ("default y if ARM || ...").
 > Or reduce IPIPE_TRACE_SHIFT for ARM, given there is a reasonable value
 > (/wrt to the tracer) your boards still boot with.

I will do some tests and propose something like that. I had this problem
with linux 2.6.15 where the initial image (I guess text + data + bss)
must fit in 3 MB. I have not tested since then.

-- 


					    Gilles Chanteperdrix.