Re: RE: RE: RE: Memory performance / Cache problem

[epsi@gmx.de]

> > Mem clock is both times 166MHz. I don't know whether are differences in
> cycle
> > access and timing, but memclock is fine.
> 
> How did you physically verify this?

Oszi show 166MHz, also the kernel message about freq are in both kernels the same.

> > Following Siarhei hints of initialize the buffers (around 1.2 MByte
> each)
> > I get different results in 22kernel for use of
> > malloc alone
> > memcpy =   473.764, loop4 =   448.430, loop1 =   102.770, rand =   
> 29.641
> > calloc alone
> > memcpy =   405.947, loop4 =   361.550, loop1 =    95.441, rand =   
> 21.853
> > malloc+memset:
> > memcpy =   239.294, loop4 =   188.617, loop1 =    80.871, rand =    
> 4.726
> >
> > In 31kernel all 3 measures are about the same (unfortunatly low) level
> of
> > malloc+memset in 22.
> 
> Yes aligned buffers can make a difference.  But probably more so for small
> copies.  Of course you must touch the memory or mprotect() it so its
> faulted in, but indications are you have done this.

Mh, alignment (to an address) is done with malloc already. Probably you mean something different. I don't understand the difference. For me is malloc+memset=calloc. 
I'll send you the benchmark code, if you like. 

> > I used a standard memcpy (think this is glib and hence not neonbased)?
> > To be neonbased I guess it has to be recompiled?
> 
> The version of glibc in use can make a difference.  CodeSourcery in 2009
> release added PLD's to mem operations.  This can give a good benefit.  It
> might be you have optimized library in one case and a non-optimized in
> another.

In both kernels I used the same rootfs (via NFS). Indeed I used CS2009q1 and its libs, but we are talking about factor 2..6. This must be something serious.

What is your feeling? Does the 22 something strange or are the newer kernels slower that they have to be.

Would be interesting to see results on other Omap3 boards with both old an new kernels.

Best regards
Steffen
-- 
GRATIS für alle GMX-Mitglieder: Die maxdome Movie-FLAT!
Jetzt freischalten unter http://portal.gmx.net/de/go/maxdome01
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html