Re: increased translation cache footprint in v2.6

[Andrew Morton <akpm@osdl.org>]

Marcelo Tosatti <marcelo.tosatti@cyclades.com> wrote:
>
> As can be seen the number of entries is more than twice (dominated by kernel addresses).

But doesn't this:

I-TLB userspace misses: 142369  I-TLB userspace misses: 2179    ITLB u: 139190
I-TLB kernel misses: 118288    	I-TLB kernel misses: 1369	ITLB k: 116319
D-TLB userspace misses: 222916 	D-TLB userspace misses: 180249	DTLB u: 38667
D-TLB kernel misses: 207773    	D-TLB kernel misses: 167236	DTLB k: 38273

mean that we're mainly missing on data accesses?

>  Sorry, I've got no list of functions for these addresses, but it was pretty obvious at the time 
>  looking at the sys_read() codepath and respective virtual addresses.
> 
>  Manual reorganization of the functions sounded too messy, although BenL mentions something about
>  fget_light() can and should be optimized.

The workload you're using also does write(), and the write() paths got
significantly deeper.

Stack misses, perhaps.  But a tlb entry caches the translation for a single
page, yes?