Andy, Pete, this patch also causes our test machines to hang hard during boot. x86_64 smp kernel, single cpu Athlon 64 machine, cpuinfo below.
Benny $ cat /proc/cpuinfo processor : 0 vendor_id : AuthenticAMD cpu family : 15 model : 79 model name : AMD Athlon(tm) 64 Processor 3800+ stepping : 2 cpu MHz : 2412.397 cache size : 512 KB fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow up pni cx16 lahf_lm svm cr8_legacy bogomips : 4828.89 TLB size : 1024 4K pages clflush size : 64 cache_alignment : 64 address sizes : 40 bits physical, 48 bits virtual power management: ts fid vid ttp tm stc Pete Zaitcev <[EMAIL PROTECTED]> wrote: > > Hi, Andi: > > The attached patch (actually, git show output) makes my Dell 1501 to hang > on boot. Sorry, I have no clue why... The culprit is found with git bisect. > But yes, it's an AMD MK-36. I use an x86_64 kernel. It is 100% reproducible. > > Cheers, > -- Pete > > commit c5bcb5635a03da3158f121ae20ccbbf72b4fc62a > Author: Andi Kleen <[EMAIL PROTECTED]> > Date: Wed May 2 19:27:21 2007 +0200 > > [PATCH] x86: Use RDTSCP for synchronous get_cycles if possible > > RDTSCP is already synchronous and doesn't need an explicit CPUID. > This is a little faster and more importantly avoids VMEXITs on > Hypervisors. > > Original patch from Joerg Roedel, but reworked by AK > Also includes miscompilation fix by Eric Biederman > > Cc: "Joerg Roedel" <[EMAIL PROTECTED]> > > Signed-off-by: Andi Kleen <[EMAIL PROTECTED]> > > diff --git a/include/asm-i386/tsc.h b/include/asm-i386/tsc.h > index 0181f9d..3f3c1fa 100644 > --- a/include/asm-i386/tsc.h > +++ b/include/asm-i386/tsc.h > @@ -38,6 +38,15 @@ static __always_inline cycles_t get_cycles_sync(void) > unsigned eax; > > /* > + * Use RDTSCP if possible; it is guaranteed to be synchronous > + * and doesn't cause a VMEXIT on Hypervisors > + */ > + alternative_io(ASM_NOP3, ".byte 0x0f,0x01,0xf9", X86_FEATURE_RDTSCP, > + "=A" (ret), "0" (0ULL) : "ecx", "memory"); > + if (ret) > + return ret; > + > + /* > * Don't do an additional sync on CPUs where we know > * RDTSC is already synchronous: > */ > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
