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kleidiai: Add runtime feature detection mechanism for aarch64/kleidiai #26076

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Merged
taronaeo merged 6 commits into from
Aug 12, 2026
Merged

kleidiai: Add runtime feature detection mechanism for aarch64/kleidiai #26076

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f8e6cd3
Add runtime feature detection mechanism for aarch64/kleidiai
JonathanC-ARM Jul 24, 2026
986ab24
Address Review Comments
JonathanC-ARM Jul 28, 2026
cb933e2
Add log warning for NSMC reserved value
JonathanC-ARM Jul 28, 2026
0fcac42
Address review comments
JonathanC-ARM Jul 31, 2026
0e71b59
Fix Rebase, move code from cpu-feats to ggml-feats
JonathanC-ARM Aug 10, 2026
c96b70b
Address naming of runtime feature struct
JonathanC-ARM Aug 10, 2026
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87 changes: 4 additions & 83 deletions ggml/src/ggml-cpu/arch/arm/cpu-feats.cpp
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Original file line number Diff line number Diff line change
@@ -1,90 +1,11 @@
#include "ggml-backend-impl.h"
#include "ggml-feats.h"

#if defined(__aarch64__)

#if defined(__linux__)
#include <sys/auxv.h>
#elif defined(__APPLE__)
#include <sys/sysctl.h>
#endif

#if !defined(HWCAP_FPHP)
#define HWCAP_FPHP (1 << 9)
#endif

#if !defined(HWCAP_ASIMDHP)
#define HWCAP_ASIMDHP (1 << 10)
#endif

#if !defined(HWCAP_ASIMDDP)
#define HWCAP_ASIMDDP (1 << 20)
#endif

#if !defined(HWCAP_SVE)
#define HWCAP_SVE (1 << 22)
#endif

#if !defined(HWCAP2_SVE2)
#define HWCAP2_SVE2 (1 << 1)
#endif

#if !defined(HWCAP2_I8MM)
#define HWCAP2_I8MM (1 << 13)
#endif

#if !defined(HWCAP2_SME)
#define HWCAP2_SME (1 << 23)
#endif

struct aarch64_features {
// has_neon not needed, aarch64 has NEON guaranteed
bool has_dotprod = false;
bool has_fp16 = false;
bool has_sve = false;
bool has_sve2 = false;
bool has_i8mm = false;
bool has_sme = false;
bool has_sme2 = false;

aarch64_features() {
#if defined(__linux__)
uint32_t hwcap = getauxval(AT_HWCAP);
uint32_t hwcap2 = getauxval(AT_HWCAP2);

has_dotprod = !!(hwcap & HWCAP_ASIMDDP);
has_fp16 = !!(hwcap & HWCAP_FPHP) && !!(hwcap & HWCAP_ASIMDHP);
has_sve = !!(hwcap & HWCAP_SVE);
has_sve2 = !!(hwcap2 & HWCAP2_SVE2);
has_i8mm = !!(hwcap2 & HWCAP2_I8MM);
has_sme = !!(hwcap2 & HWCAP2_SME);
#elif defined(__APPLE__)
int oldp = 0;
size_t size = sizeof(oldp);

if (sysctlbyname("hw.optional.arm.FEAT_DotProd", &oldp, &size, NULL, 0) == 0) {
has_dotprod = static_cast<bool>(oldp);
}

if (sysctlbyname("hw.optional.arm.FEAT_I8MM", &oldp, &size, NULL, 0) == 0) {
has_i8mm = static_cast<bool>(oldp);
}

if (sysctlbyname("hw.optional.arm.FEAT_SME", &oldp, &size, NULL, 0) == 0) {
has_sme = static_cast<bool>(oldp);
}

if (sysctlbyname("hw.optional.arm.FEAT_SME2", &oldp, &size, NULL, 0) == 0) {
has_sme2 = static_cast<bool>(oldp);
}

// Apple apparently does not implement SVE yet
#endif
}
};
#if defined(__aarch64__) || defined(_M_ARM64)

static int ggml_backend_cpu_aarch64_score() {
int score = 1;
aarch64_features af;
ggml_feats_arch64_runtime_t af = ggml_get_aarch64_runtime_features();

#ifdef GGML_USE_DOTPROD
if (!af.has_dotprod) { return 0; }
Expand Down Expand Up @@ -116,4 +37,4 @@ static int ggml_backend_cpu_aarch64_score() {

GGML_BACKEND_DL_SCORE_IMPL(ggml_backend_cpu_aarch64_score)

# endif // defined(__aarch64__)
# endif // defined(__aarch64__) || defined(_M_ARM64)
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