[UR][L0] Query timer resolution in cycles/sec for accurate timestamp#21279
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againull wants to merge 1 commit intointel:syclfrom
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[UR][L0] Query timer resolution in cycles/sec for accurate timestamp#21279againull wants to merge 1 commit intointel:syclfrom
againull wants to merge 1 commit intointel:syclfrom
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According to Level Zero the meaning of timerResolution depends on stype: - ZE_STRUCTURE_TYPE_DEVICE_PROPERTIES -> units are nanoseconds (uint64, already rounded) - ZE_STRUCTURE_TYPE_DEVICE_PROPERTIES_1_2 -> units are cycles/sec Previously we queried using ZE_STRUCTURE_TYPE_DEVICE_PROPERTIES and used the integer nanosecond value, which introduced rounding error and reduced timestamp accuracy. That could occasionally make the SYCL runtime report submit time > start time. Instead, query timerResolution with ZE_STRUCTURE_TYPE_DEVICE_PROPERTIES_1_2 (cycles/sec) and compute nanoseconds-per-cycle as a double to preserve precision.
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@intel/unified-runtime-reviewers-level-zero Could you please review. |
kswiecicki
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@intel/llvm-gatekeepers please consider merging |
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According to Level Zero spec the meaning of
timerResolutiondepends onstype:ZE_STRUCTURE_TYPE_DEVICE_PROPERTIES-> units are nanoseconds (uint64, already rounded)ZE_STRUCTURE_TYPE_DEVICE_PROPERTIES_1_2-> units are cycles/sec (exact value)Previously we queried using
ZE_STRUCTURE_TYPE_DEVICE_PROPERTIESand used the integer nanosecond value, which introduced rounding error and reduced timestamp accuracy.Instead, query
timerResolutionwithZE_STRUCTURE_TYPE_DEVICE_PROPERTIES_1_2(cycles/sec) and compute nanoseconds-per-cycle as a double to preserve precision.This fix improves the accuracy of timestamp reported from
urDeviceGetGlobalTimestampsand others.