On Fri, May 13, 2011 at 03:41:10PM -0500, Alan Cox wrote: > On 5/13/2011 2:35 PM, Matthew D Fleming wrote: > >Author: mdf > >Date: Fri May 13 19:35:01 2011 > >New Revision: 221855 > >URL: http://svn.freebsd.org/changeset/base/221855 > > > >Log: > > Move the ZERO_REGION_SIZE to a machine-dependent file, as on many > > architectures (i386, for example) the virtual memory space may be > > constrained enough that 2MB is a large chunk. Use 64K for arches > > other than amd64 and ia64, with special handling for sparc64 due to > > differing hardware. > > > > Also commit the comment changes to kmem_init_zero_region() that I > > missed due to not saving the file. (Darn the unfamiliar development > > environment). > > > > Arch maintainers, please feel free to adjust ZERO_REGION_SIZE as you > > see fit. > > > > Requested by: alc > > MFC after: 1 week > > MFC with: r221853 > > I would encourage people on platforms with virtually indexed data caches > to do a simple before and after performance test on this change, like > "dd if=/dev/zero of=/dev/null bs=64k", just to make sure that there are > no performance regressions. >
Actually, this improved the performance on an old 500MHz USIIe quite a bit, with r221854: v100# dd if=/dev/zero of=/dev/null bs=64k count=100000 100000+0 records in 100000+0 records out 6553600000 bytes transferred in 13.523223 secs (484618204 bytes/sec) with r221855: v100# dd if=/dev/zero of=/dev/null bs=64k count=100000 100000+0 records in 100000+0 records out 6553600000 bytes transferred in 5.235192 secs (1251835639 bytes/sec) Repeated runs vary only marginally in both cases. Marius _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
