Ping 2? On Sun, Apr 24, 2016 at 10:36 PM, NightStrike <nightstrike@xxxxxxxxx> wrote: > Ping? > > On Mon, Apr 18, 2016 at 12:38 AM, NightStrike <nightstrike@xxxxxxxxx> wrote: >> Also, FWIW: >> >> 1) The march=native version that uses prefetcht0 is very repeatedly >> faster by about 15% in the particular test case I'm looking at. >> >> 2) The compilers in both instances are not just the same version, they >> are the same compiler installed on an NFS mount and shared to both >> computers. >> >> >> On Mon, Apr 18, 2016 at 12:26 AM, NightStrike <nightstrike@xxxxxxxxx> wrote: >>> Not sure if this applies: >>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54210 >>> >>> If I compile on a k8 Opteron 248 with -march=native, I do not see >>> -mprfchw listed in the options in -fverbose-asm. In the assembly, I >>> see this: >>> >>> prefetcht0 (%rax) # ivtmp.1160 >>> prefetcht0 304(%rcx) # >>> prefetcht0 (%rax) # ivtmp.1160 >>> >>> If I compile on a bdver2 Opteron 6386 SE with -march=k8 (thus trying >>> to target the older system), I do see it listed in the options in >>> -fverbose-asm. In the assembly, I see this: >>> >>> prefetcht0 (%rax) # ivtmp.1160 >>> prefetcht0 304(%rcx) # >>> prefetchw (%rax) # ivtmp.1160 >>> >>> (The third line is the only difference) >>> >>> In both cases, I'm using gcc 4.9.3. Which is correct for a k8 Opteron 248?
