Re: Page cache using B-trees benchmark results

["Vishal Patil" <vishpat@gmail.com>]

Hey Andi....This is useful information....I will look into it and let
you know....
Many thanks.

- Vishal

On 18 Aug 2006 18:25:54 +0200, Andi Kleen <ak@suse.de> wrote:
> "Vishal Patil" <vishpat@gmail.com> writes:
>
> > I am attaching the benchmark results for Page Cache Implementation
> > using B-trees. I basically ran the tio (threaded i/o) benchmark
> > against my kernel (with the B-tree implementation) and the Linux
>
> I suppose you'll need some more varied benchmarks to get
> more solid data.
>
> > kernel shipped with FC5. Radix tree implementation is definately
> > better however the B-tree implementation did not suck that bad :)
>
> Have you considered trying it again instead of radix tree with
> another data structure? There are still plenty of other big
> hash tables in the kernel that might benefit from trying
> a different approach:
>
> > dmesg | grep -i hash
> PID hash table entries: 4096 (order: 12, 131072 bytes)
> Dentry cache hash table entries: 262144 (order: 9, 2097152 bytes)
> Inode-cache hash table entries: 131072 (order: 8, 1048576 bytes)
> Mount-cache hash table entries: 256
> Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
> IP route cache hash table entries: 65536 (order: 7, 524288 bytes)
> TCP established hash table entries: 262144 (order: 9, 2097152 bytes)
> TCP bind hash table entries: 65536 (order: 7, 524288 bytes)
> TCP: Hash tables configured (established 262144 bind 65536)
>
> e.g. the dentry/inode hashes are an obvious attack point.
>
> Of course you'll need benchmarks that actually stress them.
>
> -Andi
>


-- 
Motivation will almost always beat mere talent.