On 29 Aug 2014, at 17:14 , Konstantin Belousov <kostik...@gmail.com> wrote:
> On Fri, Aug 29, 2014 at 12:40:01PM +0000, Bjoern A. Zeeb wrote: >> Author: bz >> Date: Fri Aug 29 12:40:01 2014 >> New Revision: 270806 >> URL: http://svnweb.freebsd.org/changeset/base/270806 >> >> Log: >> Properly handle prefetch only for amd64 and i386 as we do elsewhere. >> >> In general theraven is right that we should factr this out and provide >> a general and per-arch implementation that everything can use. >> >> MFC after: 3 days >> X-MFC with: r270755 >> >> Modified: >> head/sys/dev/ixl/i40e_osdep.h >> >> Modified: head/sys/dev/ixl/i40e_osdep.h >> ============================================================================== >> --- head/sys/dev/ixl/i40e_osdep.h Fri Aug 29 11:18:54 2014 >> (r270805) >> +++ head/sys/dev/ixl/i40e_osdep.h Fri Aug 29 12:40:01 2014 >> (r270806) >> @@ -137,11 +137,15 @@ struct i40e_spinlock { >> >> #define le16_to_cpu >> >> +#if defined(__amd64__) || defined(i386) >> static __inline >> void prefetch(void *x) >> { >> __asm volatile("prefetcht0 %0" :: "m" (*(unsigned long *)x)); >> } > This only fix the build failure, but the code is still somewhat wrong. > > Availability of the prefetch instruction depends on the presence of SSE. We have quite a few of these as-are in the tree already; I guess they all need fixing. > Althought it is probably impossible to find a machine where the intended > hardware can operate and which does not support SSE _currently_, I am > not sure that it is wise to hard-code SSE instructions in the i386 > kernel. > > Might be, a change of the compilation test from both amd64 and i386 to > just amd64 is due. I doubt that anybody would use 40Gb with 32bit OS, > and even if somebody does, that the performace is at the stake in > this case. > I think going with David’s suggestion to do the right thing and centralise them somewhere so everything can use it is the proper way forward. I think there’s also a __builtin_prefetch(). >> +#else >> +#define prefetch(x) >> +#endif >> >> struct i40e_osdep >> { — Bjoern A. Zeeb "Come on. Learn, goddamn it.", WarGames, 1983 _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
