From: Anton Vorontsov <avoront...@mvista.com> Date: Wed, 30 Jun 2010 20:38:04 +0400
> On Tue, Jun 29, 2010 at 03:16:26PM -0700, David Miller wrote: >> >> I really don't see any value at all to this config option, >> the errata fixup code should be there all the time. > > Well, at least for eTSEC76 erratum (patch 2/3) we have to touch > fast path (i.e. start_xmit), so I just wanted to make zero > overhead for controllers that don't need any fixups. > > Not that there's much of the overhead in a single additional > 'if' condition, no. ;-) The register accesses will dominate the costs with this chip. The only case where a if() test is going to potentially create some practical performance impact is if the TX is performed purely using changes to a shared memory data structure and absolutely no MMIO register reads or writes. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
