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"sys_clock_hw_cycles_per_tick" for hpet timer? #2574

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zephyrbot opened this issue Oct 14, 2016 · 3 comments
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"sys_clock_hw_cycles_per_tick" for hpet timer? #2574

zephyrbot opened this issue Oct 14, 2016 · 3 comments
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area: Kernel bug The issue is a bug, or the PR is fixing a bug priority: low Low impact/importance bug

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@zephyrbot
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zephyrbot commented Oct 14, 2016

Reported by Sharron LIU:

I'm doing some testing on unified kernel, where "sys_clock_hw_cycles_per_tick" is not defined in the "include/kernel.h". Thus I tried to compute this value by doing:
#define CYCLES_PER_TICK (CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC/
CONFIG_SYS_CLOCK_TICKS_PER_SEC)
This comes out "250000", but the "sys_clock_hw_cycles_per_tick" used in qemu_x86 is actually "1000000". Is this as expected?

I noticed in the default configure of qemu_x86
CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=25000000
CONFIG_SYS_CLOCK_TICKS_PER_SEC=100
and I would expect "sys_clock_hw_cycles_per_tick = 250000".

(Imported from Jira ZEP-1071)

@zephyrbot
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by Benjamin Walsh:

The value in the kconfig option is overridden at runtime by the HPET, since it queries its hardware to get the real value.

@zephyrbot
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by Sharron LIU:

It's clear. Agree to close.

@zephyrbot
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by Mark Linkmeyer:

Fixing incorrect priority

@zephyrbot zephyrbot added priority: low Low impact/importance bug area: Kernel bug The issue is a bug, or the PR is fixing a bug labels Sep 23, 2017
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Labels
area: Kernel bug The issue is a bug, or the PR is fixing a bug priority: low Low impact/importance bug
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