Date: Sat, 26 Dec 2009 12:56:49 -0500 From: "b. f." <bf1783@googlemail.com> To: Luigi Rizzo <rizzo@iet.unipi.it> Cc: freebsd-current@FreeBSD.org Subject: Re: select() returning early from timeouts ? (on qemu, HEAD and RELENG_8) Message-ID: <d873d5be0912260956n2d08adc8nd504870077d9bc34@mail.gmail.com>
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>I was wondering if someone can try the above on real hardware
>and let me know.
9-CURRENT amd64 r r200984M
legacy usb support off in bios
>From loader.conf:
kern.hz="100"
hint.apic.0.clock="0"
hint.atrtc.0.clock="0"
>From sysctl.conf:
kern.timecounter.hardware=i8254
sysctl shows:
kern.clockrate: { hz = 100, tick = 10000, profhz = 100, stathz = 100 }
kern.timecounter.tick: 1
kern.timecounter.choice: TSC(800) HPET(900) ACPI-fast(1000) i8254(0)
dummy(-1000000)
kern.timecounter.hardware: i8254
kern.timecounter.stepwarnings: 0
kern.timecounter.tc.i8254.mask: 4294967295
kern.timecounter.tc.i8254.counter: 1239934843
kern.timecounter.tc.i8254.frequency: 1193182
kern.timecounter.tc.i8254.quality: 0
kern.timecounter.tc.ACPI-fast.mask: 16777215
kern.timecounter.tc.ACPI-fast.counter: 8027521
kern.timecounter.tc.ACPI-fast.frequency: 3579545
kern.timecounter.tc.ACPI-fast.quality: 1000
kern.timecounter.tc.HPET.mask: 4294967295
kern.timecounter.tc.HPET.counter: 519307291
kern.timecounter.tc.HPET.frequency: 25000000
kern.timecounter.tc.HPET.quality: 900
kern.timecounter.tc.TSC.mask: 4294967295
kern.timecounter.tc.TSC.counter: 4274176162
kern.timecounter.tc.TSC.frequency: 800000000
kern.timecounter.tc.TSC.quality: 800
kern.timecounter.invariant_tsc: 0
kern.hz: 100
#time ping -c 21 localhost
PING localhost... (127.0.0.1): 56 data bytes
64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.080 ms
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.037 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.033 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.036 ms
64 bytes from 127.0.0.1: icmp_seq=4 ttl=64 time=0.032 ms
64 bytes from 127.0.0.1: icmp_seq=5 ttl=64 time=0.033 ms
64 bytes from 127.0.0.1: icmp_seq=6 ttl=64 time=0.039 ms
64 bytes from 127.0.0.1: icmp_seq=7 ttl=64 time=0.033 ms
64 bytes from 127.0.0.1: icmp_seq=8 ttl=64 time=0.072 ms
64 bytes from 127.0.0.1: icmp_seq=9 ttl=64 time=0.034 ms
64 bytes from 127.0.0.1: icmp_seq=10 ttl=64 time=0.034 ms
64 bytes from 127.0.0.1: icmp_seq=11 ttl=64 time=0.032 ms
64 bytes from 127.0.0.1: icmp_seq=12 ttl=64 time=0.041 ms
64 bytes from 127.0.0.1: icmp_seq=13 ttl=64 time=0.038 ms
64 bytes from 127.0.0.1: icmp_seq=14 ttl=64 time=0.033 ms
64 bytes from 127.0.0.1: icmp_seq=15 ttl=64 time=0.033 ms
64 bytes from 127.0.0.1: icmp_seq=16 ttl=64 time=0.032 ms
64 bytes from 127.0.0.1: icmp_seq=17 ttl=64 time=0.032 ms
64 bytes from 127.0.0.1: icmp_seq=18 ttl=64 time=0.032 ms
64 bytes from 127.0.0.1: icmp_seq=19 ttl=64 time=0.033 ms
64 bytes from 127.0.0.1: icmp_seq=20 ttl=64 time=0.069 ms
--- localhost... ping statistics ---
21 packets transmitted, 21 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.032/0.040/0.080/0.014 ms
real 0m20.198s
user 0m0.000s
sys 0m0.002s
Apart from the possible emulation complications, the i8254 calibration
code has been removed, and there was some discussions about i8254
problems back when you outlined your callout change proposal...
Regards,
b.
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