gcc build / test times on multi-core hosts?

[H. J. Lu]

On Mon, Feb 20, 2006 at 07:30:41PM +0000, Joern RENNECKE wrote:
> the bottleneck of a shared memory bus, but the operating system must 
> allocate
> most memory locally to each CPU to avoid a bottleneck in the cross-connect
> of the processors.
> 

Linux kernel 2.6.16-rc1 and above supports

percpu_pagelist_fraction

This is the fraction of pages at most (high mark pcp->high) in each zone that
are allocated for each per cpu page list.  The min value for this is 8.  It
means that we don't allow more than 1/8th of pages in each zone to be
allocated in any single per_cpu_pagelist.  This entry only changes the value
of hot per cpu pagelists.  User can specify a number like 100 to allocate
1/100th of each zone to each per cpu page list.

The batch value of each per cpu pagelist is also updated as a result.  It is
set to pcp->high/4.  The upper limit of batch is (PAGE_SHIFT * 8)

The initial value is zero.  Kernel does not use this value at boot time to set
the high water marks for each per cpu page list.

The optimal percpu_pagelist_fraction value depends on your configuation.


H.J.