VM: cache line size?

[Aleksey Shipilev]

Hi,

I need the VM to get the info about the cache line size on the current
system. Looking around the Hotspot code, I had found the usages like this:
    intx cache_line_size = prefetch_data_size();

...where:

vm_version_sparc.hpp:
  static intx prefetch_data_size()  {
    return is_T4() ? 32 : 64;  // default prefetch block size on sparc
  }

vm_version_x86.hpp:
  static intx prefetch_data_size()  {
    intx result = 0;
    if (is_intel()) {
      result = (_cpuid_info.dcp_cpuid4_ebx.bits.L1_line_size + 1);
    } else if (is_amd()) {
      result = _cpuid_info.ext_cpuid5_ecx.bits.L1_line_size;
    }
    if (result < 32) // not defined ?
      result = 32;   // 32 bytes by default on x86 and other x64
    return result;
  }

At this point, I have a few questions:
 0. Is this the method one should use to determine the cache line size?
 1. Shouldn't that method be called cache_line_size()?
 2. Is that correct at this point that we default to 32-byte cache lines
on x86? Should we instead default for 64?

Thanks,
Aleksey.