* hpet0 versus hpet2
@ 2014-06-29 12:49 Raz
0 siblings, 0 replies; only message in thread
From: Raz @ 2014-06-29 12:49 UTC (permalink / raw)
To: linux-rt-users
Hey Rt folks
I performed a benchmark that compares the jitter of hpet2 to hpet0.
hpet0 is reserved to the kernel use ( hpet_reserve_timer(&hd, 0).
and hd.hd_irq[0] = HPET_LEGACY_8254; in arch/x86/kernel/hpet.c).
I removed these two lines.
The bellow is a histogram compares the default hpet2 to hpet0 in atom D525.
The test performed is a simple udp sender, it sends a single udp
packet each 1ms interval.
Time stamping were made by Beckhoff ET2000 ,so that the timestamps
taken by a reliable and accurate tool.
Question is whether it is possible to push a new kernel boot command
line option that gives
the user hpet0 ?
hpet0
-50 0
-40 0
-20 2
-10 14
-5 143
-1 3992
1 95217
5 544
10 74
20 14
30 0
40 0
50 0
More 0
hpet2
Bin Frequency
-50 1
-40 0
-20 0
-10 0
-5 0
-1 1
1 18
5 71
10 854
20 93098
30 237
40 1069
50 0
More 0
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2014-06-29 12:49 hpet0 versus hpet2 Raz
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