Re: increased translation cache footprint in v2.6

Paul Mackerras
2005-06-26T23:50:50Z

Marcelo Tosatti writes:

> We've noticed a slowdown while moving from v2.4 to v2.6 on a small PPC platform
> (855T CPU running at 48Mhz, containing pair of separate I/D TLB caches with
> 32 entries each), with a relatively recent kernel (v2.6.11).
>
> Test in question is a "dd" copying 16MB from /dev/zero to RAMDISK.
>
> Pinning an 8Mbyte TLB entry at KERNELBASE brought performance back to v2.4 levels.

Why are we not pinning a large TLB entry at KERNELBASE in 2.6? Was
that taken out to reduce the size of the tlb miss handler or
something?

Paul.