Use a generic implementation of the Fowler/Noll/Vo hash (FNV hash).

Make the name cache hash as well as the nfsnode hash use it.

As a special tweak, create an unsigned version of register_t.  This allows
us to use a special tweak for the 64 bit versions that significantly
speeds up the i386 version (ie: int64 XOR int64 is slower than int64
XOR int32).

The code layout is a little strange for the string function, but I was
able to get between 5 to 10% improvement over the original version I
started with. The layout affects gcc code generation choices and this way
was fastest on x86 and alpha.

Note that 'CPUTYPE=p3' etc makes a fair difference to this.  It is
around 45% faster with -march=pentiumpro on a p6 cpu.

1 files changed, 2 insertions, 28 deletions

diff --git a/sys/nfsclient/nfs_node.c b/sys/nfsclient/nfs_node.c
index 365d7f2..450729d 100644
--- a/sys/nfsclient/nfs_node.c
+++ b/sys/nfsclient/nfs_node.c
@@ -44,6 +44,7 @@
 #include <sys/namei.h>
 #include <sys/vnode.h>
 #include <sys/malloc.h>
+#include <sys/fnv_hash.h>
 
 #include <vm/vm_zone.h>
 
@@ -72,33 +73,6 @@ nfs_nhinit()
 }
 
 /*
- * Compute an entry in the NFS hash table structure
- *
- * Hash based on: http://www.isthe.com/chongo/tech/comp/fnv/
- * by Glenn Fowler, Phong Vo and Landon Curt Noll
- * aka the "Fowler / Noll / Vo Hash" (FNV)
- */
-#define FNV_32_PRIME ((u_int32_t) 0x01000193UL)
-#define FNV1_32_INIT ((u_int32_t) 33554467UL)
-u_long
-nfs_hash(fhp, fhsize)
-	nfsfh_t *fhp;
-	int fhsize;
-{
-	u_char *fhpp;
-	u_int32_t hval;
-	int i;
-
-	fhpp = &fhp->fh_bytes[0];
-	hval = FNV1_32_INIT;
-	for (i = 0; i < fhsize; i++) {
-		hval *= FNV_32_PRIME;
-		hval ^= (u_int32_t)*fhpp++;
-	}
-	return (hval);
-}
-
-/*
  * Look up a vnode/nfsnode by file handle.
  * Callers must check for mount points!!
  * In all cases, a pointer to a
@@ -133,7 +107,7 @@ nfs_nget(mntp, fhp, fhsize, npp)
 		rsflags = 0;
 
 retry:
-	nhpp = NFSNOHASH(nfs_hash(fhp, fhsize));
+	nhpp = NFSNOHASH(fnv32_hashbuf(fhp->fh_bytes, fhsize));
 loop:
 	for (np = nhpp->lh_first; np != 0; np = np->n_hash.le_next) {
 		if (mntp != NFSTOV(np)->v_mount || np->n_fhsize != fhsize ||