Re: [patch] hashtable sizes for icache and dcache

David S. Miller (davem@redhat.com)
Wed, 22 Sep 1999 13:34:23 -0700


Date: Wed, 22 Sep 1999 22:43:31 +0300
From: Matti Aarnio <matti.aarnio@sonera.fi>

Well, what processor gives that ?
At Alpha ... Depending on GCC optimization level the calculation result
of block hash is from 23 instructions (gcc optimized, 4 memory loads)
via 30 instructions (Compaq C Compiler optimized or not, along with 13
memory loads) to 42 instructions (gcc -O0, 12 memory loads)

I'm talking about the hash function value computation alone.
Once the device/ino pair and bh_hash_shift are in a register,
it is 10 instructions later that the hash value is computed.

Later,
David S. Miller
davem@redhat.com

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