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add functions to query the L1 and L2/L3 cache sizes

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Gael Guennebaud 2010-06-21 11:59:37 +02:00
parent 7196777b74
commit e54635da11
1 changed files with 70 additions and 1 deletions
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71
Eigen/src/Core/util/Memory.h
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@ -1,10 +1,11 @@
// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <g.gael@free.fr>
// Copyright (C) 2008-2010 Gael Guennebaud <g.gael@free.fr>
// Copyright (C) 2008-2009 Benoit Jacob <jacob.benoit.1@gmail.com>
// Copyright (C) 2009 Kenneth Riddile <kfriddile@yahoo.com>
// Copyright (C) 2010 Hauke Heibel <hauke.heibel@gmail.com>
// Copyright (C) 2010 Thomas Capricelli <orzel@freehackers.org>
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
@ -584,4 +585,72 @@ public:
{ return true; }
};
//---------- Cache sizes ----------
#if defined(__GNUC__)
# if defined(__PIC__) && defined(__i386__)
# define EIGEN_CPUID(abcd,func) \
__asm__ __volatile__ ("xchgl %%ebx, %%esi;cpuid; xchgl %%ebx,%%esi": "=a" (abcd[0]), "=S" (abcd[1]), "=c" (abcd[2]), "=d" (abcd[3]) : "a" (func));
# else
# define EIGEN_CPUID(abcd,func) \
__asm__ __volatile__ ("cpuid": "=a" (abcd[0]), "=b" (abcd[1]), "=c" (abcd[2]), "=d" (abcd[3]) : "a" (func) );
# endif
#elif defined(_MSC_VER)
# define EIGEN_CPUID(abcd,func) __cpuid((int*)abcd,func)
#endif
/** \internal
* \returns the size in Bytes of the L1 data cache */
inline std::ptrdiff_t ei_fetchL1CacheSize()
{
int abcd[4];
// try the direct method using extended level
EIGEN_CPUID(abcd,0x80000005);
std::ptrdiff_t l1 = std::ptrdiff_t(abcd[2] >> 24) * 1024;
if(l1>0)
return l1*1024;
// it fails, try using the standard level
EIGEN_CPUID(abcd,0x00000002);
unsigned char * bytes = reinterpret_cast<unsigned char *>(abcd)+2;
for(int i=0; i<14; ++i)
{
switch(bytes[i])
{
case 0x0A: l1 = 8; break; // 0Ah data L1 cache, 8 KB, 2 ways, 32 byte lines
case 0x0C: l1 = 16; break; // 0Ch data L1 cache, 16 KB, 4 ways, 32 byte lines
case 0x0E: l1 = 24; break; // 0Eh data L1 cache, 24 KB, 6 ways, 64 byte lines
case 0x10: l1 = 16; break; // 10h data L1 cache, 16 KB, 4 ways, 32 byte lines (IA-64)
case 0x15: l1 = 16; break; // 15h code L1 cache, 16 KB, 4 ways, 32 byte lines (IA-64)
case 0x2C: l1 = 32; break; // 2Ch data L1 cache, 32 KB, 8 ways, 64 byte lines
case 0x30: l1 = 32; break; // 30h code L1 cache, 32 KB, 8 ways, 64 byte lines
// 56h L0 data TLB, 4M pages, 4 ways, 16 entries
// 57h L0 data TLB, 4K pages, 4 ways, 16 entries
// 59h L0 data TLB, 4K pages, fully, 16 entries
case 0x60: l1 = 16; break; // 60h data L1 cache, 16 KB, 8 ways, 64 byte lines, sectored
case 0x66: l1 = 8; break; // 66h data L1 cache, 8 KB, 4 ways, 64 byte lines, sectored
case 0x67: l1 = 16; break; // 67h data L1 cache, 16 KB, 4 ways, 64 byte lines, sectored
case 0x68: l1 = 32; break; // 68h data L1 cache, 32 KB, 4 ways, 64 byte lines, sectored
// 77h code L1 cache, 16 KB, 4 ways, 64 byte lines, sectored (IA-64)
// 96h data L1 TLB, 4K...256M pages, fully, 32 entries (IA-64)
default: break;
}
}
return l1*1024;
}
/** \internal
* \returns the size in Bytes of the L2 or L3 cache if this later is present */
inline std::ptrdiff_t ei_fetchTopLevelCacheSize()
{
int abcd[4];
EIGEN_CPUID(abcd,0x80000006);
std::ptrdiff_t l2 = std::ptrdiff_t(abcd[2] >> 16) * 1024;
std::ptrdiff_t l3 = std::ptrdiff_t((abcd[3] & 0xFFFC000) >> 18) * 512 * 1024;
return std::max(l2,l3);
}
#endif // EIGEN_MEMORY_H