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Registered: ‎10-05-2010

How was libc and friends compiled (gcc options) and gcc support for extra CPU features


we are seeing some performance issues on our system (Microblaze v7.30, 100MHz, 32kB cache (I and D), divider, barrel shifter, additional machine Instructions, pattern comparator).


We use the qsort function available in glibc.

I played a bit with compiler options and with the right switch it is possible to speed up the application. qsort however is part of glibc (and heavily used in our application) which is part of the root file system from here: git://


I suppose the defaults were used and no "accelerator switches" were enabled?

B.T.W. the glibc in the rootfs is version:


# /lib/
GNU C Library stable release version 2.3.6, by Roland McGrath et al.
Copyright (C) 2005 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
Compiled by GNU CC version 4.1.2.



What I am also wondering is the usability of the extra CPU features. For example does it make sense to have a

barrel shifter when a divider and a multiplier is in the system?


I also did not find the compiler switch for "additional machine Instructions"  so does it make sense to have it enabled?







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Registered: ‎10-05-2010

With accelerator switches I mean fro example that:
-mno-xl-soft-mul -mxl-barrel-shift -mxl-pattern-compare
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