| Message ID | 1290690908-794-2-git-send-email-kadlec@blackhole.kfki.hu |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Thursday 2010-11-25 14:15, Jozsef Kadlecsik wrote: >jhash is widely used in the kernel and because the functions >are inlined, the cost in size is significant. Also, the new jhash >functions are slightly larger than the previous ones so better un-inline. >As a preparation step, the calls to the internal macros are replaced >with the plain jhash function calls. Do you have a non-normative allyesconfig/allmodconfig build whose size(1) you can run on, to show approximately just how much it differs? thanks, Jan -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 25 Nov 2010, Jan Engelhardt wrote: > On Thursday 2010-11-25 14:15, Jozsef Kadlecsik wrote: > > >jhash is widely used in the kernel and because the functions > >are inlined, the cost in size is significant. Also, the new jhash > >functions are slightly larger than the previous ones so better un-inline. > >As a preparation step, the calls to the internal macros are replaced > >with the plain jhash function calls. > > Do you have a non-normative allyesconfig/allmodconfig build whose > size(1) you can run on, to show approximately just how much it differs? In the cover mail I referred the link to the message from Ilpo Jarvinen: "I once looked into inlining cost and jhash functions were among the most wasteful (kernel-wide). Multiple jhash bodies were 100+ bytes, and the overall cost was 10k+." Best regards, Jozsef - E-mail : kadlec@blackhole.kfki.hu, kadlec@mail.kfki.hu PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt Address : KFKI Research Institute for Particle and Nuclear Physics H-1525 Budapest 114, POB. 49, Hungary -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c index 8a16280..861d252 100644 --- a/net/ipv6/inet6_connection_sock.c +++ b/net/ipv6/inet6_connection_sock.c @@ -60,18 +60,16 @@ EXPORT_SYMBOL_GPL(inet6_csk_bind_conflict); static u32 inet6_synq_hash(const struct in6_addr *raddr, const __be16 rport, const u32 rnd, const u16 synq_hsize) { - u32 a = (__force u32)raddr->s6_addr32[0]; - u32 b = (__force u32)raddr->s6_addr32[1]; - u32 c = (__force u32)raddr->s6_addr32[2]; - - a += JHASH_GOLDEN_RATIO; - b += JHASH_GOLDEN_RATIO; - c += rnd; - __jhash_mix(a, b, c); - - a += (__force u32)raddr->s6_addr32[3]; - b += (__force u32)rport; - __jhash_mix(a, b, c); + u32 c; + + c = jhash_3words((__force u32)raddr->s6_addr32[0], + (__force u32)raddr->s6_addr32[1], + (__force u32)raddr->s6_addr32[2], + rnd); + + c = jhash_2words((__force u32)raddr->s6_addr32[3], + (__force u32)rport, + c); return c & (synq_hsize - 1); } diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c index c7ba314..5e57490 100644 --- a/net/ipv6/reassembly.c +++ b/net/ipv6/reassembly.c @@ -104,26 +104,22 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr, const struct in6_addr *daddr, u32 rnd) { - u32 a, b, c; - - a = (__force u32)saddr->s6_addr32[0]; - b = (__force u32)saddr->s6_addr32[1]; - c = (__force u32)saddr->s6_addr32[2]; - - a += JHASH_GOLDEN_RATIO; - b += JHASH_GOLDEN_RATIO; - c += rnd; - __jhash_mix(a, b, c); - - a += (__force u32)saddr->s6_addr32[3]; - b += (__force u32)daddr->s6_addr32[0]; - c += (__force u32)daddr->s6_addr32[1]; - __jhash_mix(a, b, c); - - a += (__force u32)daddr->s6_addr32[2]; - b += (__force u32)daddr->s6_addr32[3]; - c += (__force u32)id; - __jhash_mix(a, b, c); + u32 c; + + c = jhash_3words((__force u32)saddr->s6_addr32[0], + (__force u32)saddr->s6_addr32[1], + (__force u32)saddr->s6_addr32[2], + rnd); + + c = jhash_3words((__force u32)saddr->s6_addr32[3], + (__force u32)daddr->s6_addr32[0], + (__force u32)daddr->s6_addr32[1], + c); + + c = jhash_3words((__force u32)daddr->s6_addr32[2], + (__force u32)daddr->s6_addr32[3], + (__force u32)id, + c); return c & (INETFRAGS_HASHSZ - 1); }
jhash is widely used in the kernel and because the functions are inlined, the cost in size is significant. Also, the new jhash functions are slightly larger than the previous ones so better un-inline. As a preparation step, the calls to the internal macros are replaced with the plain jhash function calls. Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> --- net/ipv6/inet6_connection_sock.c | 18 ++++++++---------- net/ipv6/reassembly.c | 36 ++++++++++++++++-------------------- 2 files changed, 24 insertions(+), 30 deletions(-)