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Using fallback when the (none)feature bit is present.

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This commit is contained in:
David Carlier
2020-03-13 16:46:16 +00:00
parent e7f020cf76
commit 6b8650e4ce
2 changed files with 12 additions and 22 deletions
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20
src/aal/aal.h
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@@ -12,10 +12,6 @@
#if defined(__arm__) || defined(__aarch64__)
# define PLATFORM_IS_ARM
/**
* on ARM cpu counters are accessible only in privileged mode
*/
# define SNMALLOC_NO_ALL_CPUCOUNTERS
#endif
namespace snmalloc
@@ -31,6 +27,10 @@ namespace snmalloc
* and so may use bit operations on pointer values.
*/
IntegerPointers = (1 << 0),
/**
* This architecture cannot access cpu cycles counters from userspace
*/
NoCpuCycleCounters = (1 << 1),
};
/**
@@ -68,12 +68,14 @@ namespace snmalloc
*/
static inline uint64_t tick()
{
#if defined(SNMALLOC_NO_ALL_CPUCOUNTERS)
struct timespec n = {0, 0ul};
clock_gettime(CLOCK_MONOTONIC, &n);
if constexpr((Arch::aal_features & NoCpuCycleCounters) == NoCpuCycleCounters)
{
struct timespec n = {0, 0ul};
clock_gettime(CLOCK_MONOTONIC, &n);
return static_cast<uint64_t>((n.tv_sec) * (1000000000 * n.tv_nsec));
#elif __has_builtin(__builtin_readcyclecounter) && \
return static_cast<uint64_t>((n.tv_sec) * (1000000000 * n.tv_nsec));
}
#if __has_builtin(__builtin_readcyclecounter) && \
!defined(SNMALLOC_NO_AAL_BUILTINS)
return __builtin_readcyclecounter();
#else

14
src/aal/aal_arm.h
View File

@@ -18,7 +18,7 @@ namespace snmalloc
/**
* Bitmap of AalFeature flags
*/
static constexpr uint64_t aal_features = IntegerPointers;
static constexpr uint64_t aal_features = IntegerPointers | NoCpuCycleCounters;
/**
* On pipelined processors, notify the core that we are in a spin loop and
* that speculative execution past this point may not be a performance gain.
@@ -27,18 +27,6 @@ namespace snmalloc
{
__asm__ volatile("yield");
}
/**
* Issue a prefetch hint at the specified address.
*/
static inline void prefetch(void*)
{
}
static inline uint64_t tick()
{
return 0ull;
}
};
using AAL_Arch = AAL_arm;