spl-time: Use KeQueryPerformanceCounter instead of KeQueryTickCount #326
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Maybe I should remove |
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I also noticed the performance benchmarks for checksums / raidz parity use this to select an algorithm, should make the results more accurate. |
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Maybe we should assert for |
lundman
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I added the |
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`KeQueryTickCount` seems to only have a 15.625ms resolution unless the interrupt timer frequency is increased, which should be avoided due to power usage. Instead, this switches the `zfs_lbolt`, `gethrtime` and `random_get_bytes` to use `KeQueryPerformanceCounter`. On my system this gives a 100ns resolution. Signed-off-by: Axel Gembe <[email protected]>
One less division for each call. Signed-off-by: Axel Gembe <[email protected]>
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…326) * spl-time: Use KeQueryPerformanceCounter instead of KeQueryTickCount `KeQueryTickCount` seems to only have a 15.625ms resolution unless the interrupt timer frequency is increased, which should be avoided due to power usage. Instead, this switches the `zfs_lbolt`, `gethrtime` and `random_get_bytes` to use `KeQueryPerformanceCounter`. On my system this gives a 100ns resolution. Signed-off-by: Axel Gembe <[email protected]> * spl-time: Add assertion to gethrtime and cache NANOSEC / freq division One less division for each call. Signed-off-by: Axel Gembe <[email protected]> --------- Signed-off-by: Axel Gembe <[email protected]>
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KeQueryTickCountseems to only have a 15.625ms resolution unless the interrupt timer frequency is increased, which should be avoided due to power usage.Instead, this switches the
zfs_lbolt,gethrtimeandrandom_get_bytesto useKeQueryPerformanceCounter.On my system this gives a 100ns resolution.