Dear Raphael, in message <42E0B826.2070800 at gmx.de> you wrote: > > Debian GNU/Linux v3.1 (Sarge) is out so give it a try on my MPC850 > running Debian v3.0 for more then 1 year with Denx's 2.4.20 kernel. > > It failed with more or less the same reason as described May 2004 > in this posting > http://lists.debian.org/debian-embedded/2004/05/msg00032.html > > Things changed since May 2004 but the problem seams to be. I'm using > 100% binary compatible Debian GNU/Linux 3.0 (Woody) without any > problems on my MPC860 board with kernel FPU emulation enabled. This > math-emu implementation seams to be stable enought to work with libc6 > 2.2.5 and very many server application and large C++ application at high > load (our stress tests are really horrible for the compleate system!).
I guess you are aware that the FPU emulation is a nightmare perfor- mance-wise - you take a kernel exception for each and every FP instruction. FP execution is several orders faster when you use soft-float (which, of course, requires all soft-float libraries, too). > I've also heard from people on IRC that 100% Sarge works for them on > FPU-less MPC boards without trouble. So while I'm investigating the > problem would like to hear some more respond on this issue from > people who spend more time on getting Sarge running with 100% Debian > v3.1 (Sarge) on their MPC8xx environment. This is probably not a FP issue but may be related to the cache line size and/or the infamous "dcbz" misbehaviour. The standard fix (removing memset.S when building glibc) has been discussed many times before; see for example the patches / build scripts for our EDK or Dan Kegel's crosstool. > The -msoft-float advice is not what I'm looking for. I'm not sure if > the FPU is responsible for the problem. Maybe the Debian libc6 2.3.2 > package is missing something important for the MPC8xx PowerPC (the > cache-line-size is 4 for Debian's libc on PowerPC by default). The 4 what? Bytes? > big advantage using a standard distribution is the big number of > precompiled packages. I do not intent to recompile more then 18000 > due to this first failed tests. You don't intend to use 18000 packages on your embedded system either ;-) Best regards, Wolfgang Denk -- Software Engineering: Embedded and Realtime Systems, Embedded Linux Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de "Free markets select for winning solutions." - Eric S. Raymond
