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Add recognition of new Atom CPUs

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This commit is contained in:
Andrea Mazzoleni 2015-06-04 22:38:32 +02:00
parent e15767d222
commit 2ae9d8d41a
3 changed files with 64 additions and 10 deletions
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4
HISTORY
View file

@ -1,6 +1,10 @@
SnapRAID HISTORY
================
8.2 2015/06
===========
* Update 'best' RAID functions for recent Atom CPUs.
8.1 2015/05
===========
* Fix build issues in generic Unix platforms, including Mac OS X.

66
raid/cpu.h
View file

@ -212,6 +212,38 @@ static inline int raid_cpu_has_avx512bw(void)
(3 << 1) | (7 << 5)); /* OS saves XMM, YMM and ZMM registers */
}
/**
* Check if it's an Intel Atom CPU.
*/
static inline int raid_cpu_is_atom(unsigned family, unsigned model)
{
if (family != 6)
return 0;
/*
* x86 Architecture CPUID
* http://www.sandpile.org/x86/cpuid.htm
*
* Intel Atom
* 1C (28) Atom (45 nm) with 512 KB on-die L2
* 26 (38) Atom (45 nm) with 512 KB on-die L2
* 36 (54) Atom (32 nm) with 512 KB on-die L2
* 27 (39) Atom (32 nm) with 512 KB on-die L2
* 35 (53) Atom (?? nm) with ??? KB on-die L2
* 4A (74) Atom 2C (22 nm) 1 MB L2 + PowerVR (TGR)
* 5A (90) Atom 4C (22 nm) 2 MB L2 + PowerVR (ANN)
* 37 (55) Atom 4C (22 nm) 2 MB L2 + Intel Gen7 (BYT)
* 4C (76) Atom 4C (14 nm) 2 MB L2 + Intel Gen8 (BSW)
* 5D (93) Atom 4C (28 nm TSMC) 1 MB L2 + Mali (SoFIA)
* 4D (77) Atom 8C (22 nm) 4 MB L2 (AVN)
* ?? Atom ?C (14 nm) ? MB L2 (DVN)
*/
return model == 28 || model == 38 || model == 54
|| model == 39 || model == 53 || model == 74
|| model == 90 || model == 55 || model == 76
|| model == 93 || model == 77;
}
/**
* Check if the processor has a slow MULT implementation.
* If yes, it's better to use a hash not based on multiplication.
@ -222,16 +254,21 @@ static inline int raid_cpu_has_slowmult(void)
unsigned family;
unsigned model;
/*
* In some cases Murmur3 based on MUL instruction,
* is a LOT slower than Spooky2 based on SHIFTs.
*/
raid_cpu_info(vendor, &family, &model);
if (strcmp(vendor, "GenuineIntel") == 0) {
/*
* Intel Atom
* Murmur3 based on MUL instruction, is a lot slower
* than Spooky2 based on SHIFTs.
* Like: 378 MB/s vs 3413 MB/s
* Intel Atom (Model 28)
* murmur3:378 MB/s, spooky2:3413 MB/s (x86)
*
* Intel Atom (Model 77)
* murmur3:1311 MB/s, spooky2:4056 MB/s (x64)
*/
if (family == 6 && model == 28)
if (raid_cpu_is_atom(family, model))
return 1;
}
@ -248,19 +285,32 @@ static inline int raid_cpu_has_slowextendedreg(void)
unsigned family;
unsigned model;
/*
* In some cases the PAR2 implementation using 16 SSE registers
* is a LITTLE slower than the one using only the first 8 registers.
* This doesn't happen for PARZ.
*/
raid_cpu_info(vendor, &family, &model);
if (strcmp(vendor, "AuthenticAMD") == 0) {
/*
* AMD Bulldozer
* PAR1/PAR2 implementations using 16 SSE registers are slower
* than ones using only the first 8 registers.
* Like: 4465 MB/s vs 4922 MB/s.
* par2_sse2:4922 MB/s, par2_sse2e:4465 MB/s
*/
if (family == 21)
return 1;
}
if (strcmp(vendor, "GenuineIntel") == 0) {
/*
* Intel Atom (Model 77)
* par2_sse2:5686 MB/s, par2_sse2e:5250 MB/s
* parz_sse2:3100 MB/s, parz_sse2e:3400 MB/s
*/
if (raid_cpu_is_atom(family, model))
return 1;
}
return 0;
}
#endif

4
raid/module.c
View file

@ -50,11 +50,11 @@ void raid_init(void)
#ifdef CONFIG_X86_64
if (raid_cpu_has_slowextendedreg()) {
raid_gen_ptr[1] = raid_gen2_sse2;
raid_genz_ptr = raid_genz_sse2;
} else {
raid_gen_ptr[1] = raid_gen2_sse2ext;
raid_genz_ptr = raid_genz_sse2ext;
}
/* note that raid_cpu_has_slowextendedreg() doesn't affect parz */
raid_genz_ptr = raid_genz_sse2ext;
#else
raid_gen_ptr[1] = raid_gen2_sse2;
raid_genz_ptr = raid_genz_sse2;