- Implement
uint32_t namei_hash(const char *p, const char **ep) which determines the equivalent MI hash32_str() hash for p. If *ep != NULL, calculate the hash to the character before ep. If *ep == NULL, calculate the has to the first / or NUL found, and point *ep to that location. - Use namei_hash() to calculate cn_hash in lookup() and relookup(). Hash distribution goes from 35-40% to 55-70%, with similar profiled time spent in cache_lookup() and cache_enter() on my P3-600. - Use namei_hash() to calculate cn_hash in nfs_readdirplusrpc(), insetad of homegrown code (that differed from that in lookup() !) namei_hash() has better spread and is faster than previous code (which used a non-constant multiplication).
This commit is contained in:
lukem
parent
df8cfd38a2
commit
290cc55a28
@ -1,4 +1,4 @@
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/* $NetBSD: vfs_lookup.c,v 1.38 2001/11/12 15:25:39 lukem Exp $ */
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/* $NetBSD: vfs_lookup.c,v 1.39 2001/12/08 04:09:59 lukem Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1989, 1993
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@ -41,7 +41,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.38 2001/11/12 15:25:39 lukem Exp $");
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__KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.39 2001/12/08 04:09:59 lukem Exp $");
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#include "opt_ktrace.h"
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@ -53,8 +53,9 @@ __KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.38 2001/11/12 15:25:39 lukem Exp $"
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/errno.h>
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#include <sys/malloc.h>
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#include <sys/filedesc.h>
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#include <sys/hash.h>
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#include <sys/malloc.h>
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#include <sys/proc.h>
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#ifdef KTRACE
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@ -235,6 +236,34 @@ namei(ndp)
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return (error);
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}
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/*
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* Determine the namei hash (for cn_hash) for name.
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* If *ep != NULL, hash from name to ep-1.
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* If *ep == NULL, hash from name until the first NUL or '/', and
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* return the location of this termination character in *ep.
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*
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* This function returns an equivalent hash to the MI hash32_strn().
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* The latter isn't used because in the *ep == NULL case, determining
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* the length of the string to the first NUL or `/' and then calling
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* hash32_strn() involves unnecessary double-handling of the data.
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*/
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uint32_t
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namei_hash(const char *name, const char **ep)
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{
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uint32_t hash;
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hash = HASH32_STR_INIT;
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if (*ep != NULL) {
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for (; name < *ep; name++)
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hash = hash * 33 + *(uint8_t *)name;
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} else {
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for (; *name != '\0' && *name != '/'; name++)
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hash = hash * 33 + *(uint8_t *)name;
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*ep = name;
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}
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return (hash + (hash >> 5));
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}
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/*
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* Search a pathname.
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* This is a very central and rather complicated routine.
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@ -349,9 +378,8 @@ dirloop:
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* responsibility for freeing the pathname buffer.
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*/
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cnp->cn_consume = 0;
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cnp->cn_hash = 0;
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for (cp = cnp->cn_nameptr; *cp != '\0' && *cp != '/'; cp++)
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cnp->cn_hash += (unsigned char)*cp;
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cp = NULL;
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cnp->cn_hash = namei_hash(cnp->cn_nameptr, &cp);
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cnp->cn_namelen = cp - cnp->cn_nameptr;
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if (cnp->cn_namelen > NAME_MAX) {
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error = ENAMETOOLONG;
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@ -638,8 +666,8 @@ relookup(dvp, vpp, cnp)
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* responsibility for freeing the pathname buffer.
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*/
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#ifdef NAMEI_DIAGNOSTIC
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for (newhash = 0, cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++)
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newhash += (unsigned char)*cp;
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cp = NULL;
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newhash = namei_hash(cnp->cn_nameptr, &cp);
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if (newhash != cnp->cn_hash)
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panic("relookup: bad hash");
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if (cnp->cn_namelen != cp - cnp->cn_nameptr)
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@ -1,4 +1,4 @@
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/* $NetBSD: nfs_vnops.c,v 1.146 2001/12/04 18:38:09 christos Exp $ */
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/* $NetBSD: nfs_vnops.c,v 1.147 2001/12/08 04:10:00 lukem Exp $ */
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/*
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* Copyright (c) 1989, 1993
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@ -43,7 +43,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: nfs_vnops.c,v 1.146 2001/12/04 18:38:09 christos Exp $");
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__KERNEL_RCSID(0, "$NetBSD: nfs_vnops.c,v 1.147 2001/12/08 04:10:00 lukem Exp $");
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#include "opt_nfs.h"
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#include "opt_uvmhist.h"
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@ -62,6 +62,7 @@ __KERNEL_RCSID(0, "$NetBSD: nfs_vnops.c,v 1.146 2001/12/04 18:38:09 christos Exp
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#include <sys/vnode.h>
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#include <sys/dirent.h>
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#include <sys/fcntl.h>
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#include <sys/hash.h>
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#include <sys/lockf.h>
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#include <sys/stat.h>
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#include <sys/unistd.h>
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@ -2377,7 +2378,6 @@ nfs_readdirplusrpc(vp, uiop, cred)
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struct componentname *cnp = &ndp->ni_cnd;
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struct nfsmount *nmp = VFSTONFS(vp->v_mount);
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struct nfsnode *dnp = VTONFS(vp), *np;
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const unsigned char *hcp;
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nfsfh_t *fhp;
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u_quad_t fileno;
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int error = 0, tlen, more_dirs = 1, blksiz = 0, doit, bigenough = 1, i;
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@ -2522,14 +2522,15 @@ nfs_readdirplusrpc(vp, uiop, cred)
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newvp = NFSTOV(np);
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}
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if (!error) {
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const char *cp;
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nfs_loadattrcache(&newvp, &fattr, 0);
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dp->d_type =
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IFTODT(VTTOIF(np->n_vattr->va_type));
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ndp->ni_vp = newvp;
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cnp->cn_hash = 0;
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for (hcp = cnp->cn_nameptr, i = 1; i <= len;
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i++, hcp++)
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cnp->cn_hash += *hcp * i;
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cp = cnp->cn_nameptr + cnp->cn_namelen;
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cnp->cn_hash =
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namei_hash(cnp->cn_nameptr, &cp);
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if (cnp->cn_namelen <= NCHNAMLEN)
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cache_enter(ndp->ni_dvp, ndp->ni_vp,
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cnp);
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@ -1,4 +1,4 @@
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/* $NetBSD: namei.h,v 1.24 2001/12/06 04:02:22 lukem Exp $ */
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/* $NetBSD: namei.h,v 1.25 2001/12/08 04:10:00 lukem Exp $ */
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/*
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* Copyright (c) 1985, 1989, 1991, 1993
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@ -184,6 +184,7 @@ extern struct pool_cache pnbuf_cache; /* pathname buffer cache */
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#define PNBUF_PUT(pnb) pool_cache_put(&pnbuf_cache, (pnb))
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int namei __P((struct nameidata *ndp));
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uint32_t namei_hash __P((const char *, const char **));
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int lookup __P((struct nameidata *ndp));
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int relookup __P((struct vnode *dvp, struct vnode **vpp,
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struct componentname *cnp));
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