* what cflag/march to use for intel core duo l2400? @ 2006-06-08 3:29 George Nychis 2006-06-08 4:32 ` Tim Prince 0 siblings, 1 reply; 4+ messages in thread From: George Nychis @ 2006-06-08 3:29 UTC (permalink / raw) To: gcc-help Hi, I was wondering what march to specify in my cflags for the Intel Core Duo L2400 processor. The gentoo-wiki says that the safe cflag is prescott, but I figured I would ask here to find the optimal for this processor, or if the prescott is truly the safest/optimal. Here is my /proc/cpuinfo for it: processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 14 model name : Genuine Intel(R) CPU L2400 @ 1.66GHz stepping : 8 cpu MHz : 1662.571 cache size : 2048 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx pni monitor vmx est tm2 xtpr bogomips : 3331.72 processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 14 model name : Genuine Intel(R) CPU L2400 @ 1.66GHz stepping : 8 cpu MHz : 1662.571 cache size : 2048 KB physical id : 0 siblings : 2 core id : 1 cpu cores : 2 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx pni monitor vmx est tm2 xtpr bogomips : 3325.15 - George ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: what cflag/march to use for intel core duo l2400? 2006-06-08 3:29 what cflag/march to use for intel core duo l2400? George Nychis @ 2006-06-08 4:32 ` Tim Prince 2006-06-09 0:33 ` George Nychis 0 siblings, 1 reply; 4+ messages in thread From: Tim Prince @ 2006-06-08 4:32 UTC (permalink / raw) To: George Nychis; +Cc: gcc-help George Nychis wrote: > Hi, > > I was wondering what march to specify in my cflags for the Intel Core > Duo L2400 processor. The gentoo-wiki says that the safe cflag is > prescott, but I figured I would ask here to find the optimal for this > processor, or if the prescott is truly the safest/optimal. The wiki might be right, if you are using the same gcc version they have in mind. How are we to know? Might there a conflict between safety and optimality? Do you disqualify gcc-4.2 on grounds of safety? Surely, it would often generate better code, and avoid the question of what -march option to choose. ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: what cflag/march to use for intel core duo l2400? 2006-06-08 4:32 ` Tim Prince @ 2006-06-09 0:33 ` George Nychis 2006-06-09 1:49 ` Tim Prince 0 siblings, 1 reply; 4+ messages in thread From: George Nychis @ 2006-06-09 0:33 UTC (permalink / raw) To: tprince; +Cc: gcc-help Tim Prince wrote: > George Nychis wrote: > >> Hi, >> >> I was wondering what march to specify in my cflags for the Intel Core >> Duo L2400 processor. The gentoo-wiki says that the safe cflag is >> prescott, but I figured I would ask here to find the optimal for this >> processor, or if the prescott is truly the safest/optimal. > > The wiki might be right, if you are using the same gcc version they have > in mind. How are we to know? Might there a conflict between safety and > optimality? > Do you disqualify gcc-4.2 on grounds of safety? Surely, it would often > generate better code, and avoid the question of what -march option to > choose. > I'd prefer sticking to gcc-4.1 Check out this response i got on the lkml about the architecture: >> My guess is the "Pentium-4/Celeron(P4-based)/Pentium-4 M/Xeon" >family, >> but maybe someone has a different opinion or can support it. >> >> Here is the /proc/cpuinfo: >> processor : 0 >> vendor_id : GenuineIntel >> cpu family : 6 >> model : 14 > >[snip] > >"Pentium-4/Celeron(P4-based)/Pentium-4 M/Xeon" are all family 15, not >family 6. > >I have a Pentium M, it's family 6 model 13. Also, AFAIK the Intel Core >is based on the Pentium M (which in turn is based on Pentium III). So, >my personal best guess would be to choose "Pentium M". > >Unfortunately, I don't have one of these (Intel Core) at this point, >so I can't test it myself... So, this person has a pentium m, and /proc/cpu info says his processor belongs to family 6... as you can see, mine also belongs to family 6... so even though the wiki stages march=prescott, what do you guys think? - George ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: what cflag/march to use for intel core duo l2400? 2006-06-09 0:33 ` George Nychis @ 2006-06-09 1:49 ` Tim Prince 0 siblings, 0 replies; 4+ messages in thread From: Tim Prince @ 2006-06-09 1:49 UTC (permalink / raw) To: George Nychis; +Cc: tprince, gcc-help George Nychis wrote: > > > I'd prefer sticking to gcc-4.1 > > So, this person has a pentium m, and /proc/cpu info says his processor > belongs to family 6... as you can see, mine also belongs to family 6... > so even though the wiki stages march=prescott, what do you guys think? > -march=pentium-m prefers x87 over sse scalar code, because pentium-m can decode sse at only half the rate of x87. You should see the speed advantage clearly on pentium-m, presumably not on Core Duo. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2006-06-09 1:49 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2006-06-08 3:29 what cflag/march to use for intel core duo l2400? George Nychis 2006-06-08 4:32 ` Tim Prince 2006-06-09 0:33 ` George Nychis 2006-06-09 1:49 ` Tim Prince
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