From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikita Danilov Subject: Re: Performance improvements to key comparison functions Date: Tue, 13 Jul 2004 00:04:08 +0400 Message-ID: <16626.61112.905268.684688@laputa.namesys.com> References: <20040712183919.0958A15F92@mail03.powweb.com> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: <20040712183919.0958A15F92@mail03.powweb.com> List-Id: Content-Type: text/plain; charset="iso-8859-1" To: David Dabbs Cc: reiserfs-list@namesys.com David Dabbs writes: >=20 > If you downloaded the code at http://dabbs.net/reiser4 I have uploaded a= new > zip file. I posted an incorrect version when I uploaded it in the wee ho= urs > this morning.=20 ---------------------------------------------------------------------- static inline cmp_t_new keycmp_new( const reiser4_key * k1 /* first key to compare */ , const reiser4_key * k2 /* second key to compare */ ) { __u64 v1, v2; =20 if ((v1=3Dget_key_el(k1,0)) !=3D (v2=3Dget_key_el(k2,0))) return (v1 > v2); if ((v1=3Dget_key_el(k1,1)) !=3D (v2=3Dget_key_el(k2,1)))=20 return (v1 > v2); if ((v1=3Dget_key_el(k1,2)) !=3D (v2=3Dget_key_el(k2,2))) return (v1 > v2);=20 if ((v1=3Dget_key_el(k1,3)) !=3D (v2=3Dget_key_el(k2,3))) return (v1 > v2); =20 return EQUAL_TO_NEW; } ---------------------------------------------------------------------- Note that comparisons in C (like (v1 > v2)) are not guaranteed to return 0 or _1_ as a result, but simply zero, or _non-zero_. Standard trick to "normalize" comparison result is to do return !!(v1 > v2)); etc. In the same vein, "isunique" argument of znode_contains_key_strict_new() is not guaranteed to be 0 or 1, which renders this function wrong. That said, I think that proper way to test your functions is to plug them into kernel reiser4 version and run some CPU intensive tests. > =A0=A0 > David >=20 >=20 Good luck, Nikita. >=20