On Wed, Sep 15, 2010 at 8:06 AM, Thomas Pornin <thomas.por...@cryptolog.com> wrote: > Hello all, > > gcc38 is documented to be a PS3, with a 3.2 Ghz Cell processor (PowerPC > architecture). Every (integer) code I run on it seems "sluggish". This > covers both my own C and assembly code, and, for instance, OpenSSL: > "openssl speed sha256" reports a top hashing speed of about 52 MB/s, as > if the CPU was running at 1 GHz or so.
No most likely what is happening is the code invokes cell microcode which is bad for performance. There is a 7 cycle bubble just to decode the instruction (if microcoded) and then the instructions are executed and at that point turns off the other hardware thread while they are being executed. Though it might be because the two hardware threads are making it seem like a dual 1.6GHz processor instead because of the way the threading is implemented. You really need to use oprofile to understand what is going on. The cell PowerPC is an ok processor really not designed for way high performance. The SPU is what gives the cell the performance benefit. Thanks, Andrew Pinski _______________________________________________ Gcc-cfarm-users mailing list Gcc-cfarm-users@gna.org https://mail.gna.org/listinfo/gcc-cfarm-users
