On 13.1.2010 17:02, Andi Kleen wrote: [...] > This patch increases the hash table size to a larger prime > and switches to a FNV32 hash. I played around with a couple of hash > functions, but that one seemed to perform best with reasonable > hash table sizes. > > Increasing the hash table size even further didn't > seem like a good idea, because there are a couple of global > walks which walk the complete hash table. > > I also moved the unnamed bucket to 0. It's still the longest > of all the buckets (44 entries), but hopefully it's not > often hit except for the global walk which doesn't care. > > The result is a much nicer distribution: > (first column bucket length, second number of buckets with that length) > > 1: 3505 > 2: 1236 > 3: 294 > 4: 52 > 5: 3 > 47: 1 <--- this is the unnamed symbols bucket > > There are still some 5+ buckets, but increasing the hash table > even more would be likely not worth it. > > This also cleans up the code slightly by removing hard coded > magic numbers. > > I didn't notice a big performance difference either way > on my Nehalem system, but I presume it'll help somewhat > on slower systems. > > --- > scripts/kconfig/expr.h | 5 ++--- > scripts/kconfig/symbol.c | 29 +++++++++++++++++------------ > scripts/kconfig/zconf.tab.c_shipped | 2 +- > scripts/kconfig/zconf.y | 2 +- > 4 files changed, 21 insertions(+), 17 deletions(-) Hi Andi, The patch looks ok, but you forgot your Signed-off-by line? Michal -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
