Livelock limit engaged?
Dave Hayes
dave at jetcafe.org
Fri Aug 10 16:28:55 PDT 2007
Matthew Dillon <dillon at apollo.backplane.com> writes:
> run vmstat -i
# vmstat -i
interrupt total rate
clk 281783 437
atkbd0 4 0
sio0 0 0
fdc0 0 0
ppc0 18 0
acpi0/em0 0 0
uhci0 0 0
uhci1/uhci2/uhci3/twe0/fxp0/atapci1/atapci1 6766087 10506
ata0 12463 19
ata1 0 0
irq19 101 0
swi_siopoll 0 0
swi_crypto/swi_camnet 0 0
swi_cambio 0 0
swi_vm 0 0
swi_taskq 0 0
Total 7060456 10963
Ok I see the interrupt in question. (I don't suppose there is any way to
move the USB interrupts to another less used IRQ?)
> Monitor your interrupt rate with systat -vm 1
> If the interrupt rate is normal for the workload on the machine,
There's a good question. Define "normal". :) I have no idea what normal
is, this is a brand new box.
Here's a vmstat -i from a production machine that is doing your basic
web/email/DNS:
# vmstat -i
interrupt total rate
clk 784643353 281
atkbd0 1 0
sio0 0 0
ppc0 1 0
acpi0/em0 0 0
uhci0 0 0
uhci1/uhci2/uhci3/twe0/fxp0/atapci1/atapci1 75223514 26
ata0 71880 0
ata1 0 0
irq19 96 0
swi_siopoll 0 0
swi_crypto/swi_camnet 0 0
swi_cambio 0 0
swi_vm 0 0
swi_taskq 0 0
Total 859938845 308
The two machines are supposed to be identical, but obviously they
aren't. (The last one was bought recently, the previous one in April.)
If I do your systat -vm 1, I hardly see a peak interrupt rate on
the production machine, but the new machine spikes to 30-40%.
Both motherboards are D946GZIS Intel, identical as far as I can
tell from the model and packaging.
Attached is also a sysctl -a hw. I did a diff between the old
and new machines on this:
2c2
< hw.model: Intel(R) Core(TM)2 CPU 6400 @ 2.13GHz
---
> hw.model: Intel(R) Core(TM)2 CPU 6420 @ 2.13GHz
5,6c5,6
< hw.physmem: 2062254080
< hw.usermem: 1860755456
---
> hw.physmem: 2061856768
> hw.usermem: 2007019520
53c53
< hw.availpages: 503514
---
> hw.availpages: 503513
55c55
< hw.i8254.timestamp: 00000000 00151b77cbbffe68
---
> hw.i8254.timestamp: 00000000 000002dde46d87d0
Anything else I can probe?
------
Dave Hayes - Consultant - Altadena CA, USA - dave at jetcafe.org
>>> The opinions expressed above are entirely my own <<<
The universal body of reality is so subtle that you do not
hear it when you deliberately listen for it, and you do not
see it when you look at it. As for the pure knowledge that
has no teacher, how can it be attained by thought or study?
new# sysctl -a hw
hw.machine: i386
hw.model: Intel(R) Core(TM)2 CPU 6420 @ 2.13GHz
hw.ncpu: 1
hw.byteorder: 1234
hw.physmem: 2061856768
hw.usermem: 2007019520
hw.pagesize: 4096
hw.floatingpoint: 1
hw.machine_arch: i386
hw.platform: pc32
hw.aac.iosize_max: 65536
hw.cbb.start_memory: 2281701376
hw.cbb.start_16_io: 256
hw.cbb.start_32_io: 4096
hw.cbb.debug: 0
hw.cardbus.debug: 0
hw.cardbus.cis_debug: 0
hw.an.an_dump: off
hw.an.an_cache_mode: dbm
hw.an.an_cache_mcastonly: 0
hw.an.an_cache_iponly: 1
hw.ata.mpipe_size: 4
hw.ata.ata_dma: 1
hw.ata.wc: 1
hw.ata.tags: 0
hw.ata.atapi_dma: 0
hw.firewire.try_bmr: 1
hw.firewire.hold_count: 3
hw.firewire.fwmem.eui64_hi: 0
hw.firewire.fwmem.eui64_lo: 0
hw.firewire.fwmem.speed: 2
hw.firewire.fwe.stream_ch: 1
hw.firewire.fwe.tx_speed: 2
hw.firewire.fwe.rx_queue_len: 128
hw.firewire.sbp.auto_login: 1
hw.firewire.sbp.max_speed: -1
hw.firewire.sbp.exclusive_login: 1
hw.firewire.sbp.login_delay: 1000
hw.firewire.sbp.scan_delay: 500
hw.firewire.sbp.tags: 0
hw.fxp_rnr: 0
hw.wi.txerate: 0
hw.wi.debug: 0
hw.rtw.rfprog_fallback: 0
hw.rtw.host_rfio: 0
hw.rtw.chip_reset: 0
hw.xe.debug: 1
hw.pccard.debug: 0
hw.pccard.cis_debug: 0
hw.dc_quick: 1
hw.usb.ugen.bufsize: 16384
hw.instruction_sse: 1
hw.availpages: 503513
hw.i8254.freq: 1193182
hw.i8254.timestamp: 00000000 000002dde46d87d0
hw.pci_disable_bios_route: 0
hw.acpi.supported_sleep_state: S3 S4 S5
hw.acpi.power_button_state: S5
hw.acpi.sleep_button_state: S3
hw.acpi.lid_switch_state: NONE
hw.acpi.standby_state: S1
hw.acpi.suspend_state: S3
hw.acpi.sleep_delay: 1
hw.acpi.s4bios: 0
hw.acpi.verbose: 0
hw.acpi.disable_on_poweroff: 0
hw.acpi.reset_video: 1
hw.acpi.cpu.throttle_max: 8
hw.acpi.cpu.throttle_state: 8
hw.acpi.cpu.performance_speed: 8
hw.acpi.cpu.economy_speed: 4
hw.acpi.cpu.cx_supported: C1/0
hw.acpi.cpu.cx_lowest: C1
hw.acpi.cpu.cx_usage: 100.00%
hw.twe0.driver_version: 1.40.01.002
hw.em0.debug_info: -1
hw.em0.stats: -1
hw.em0.rx_int_delay: 0
hw.em0.tx_int_delay: 66
hw.em0.rx_abs_int_delay: 66
hw.em0.tx_abs_int_delay: 66
hw.em0.int_throttle_ceil: 10000
hw.fxp0.int_delay: 1000
hw.fxp0.bundle_max: 6
old# systcl -a hw
hw.machine: i386
hw.model: Intel(R) Core(TM)2 CPU 6400 @ 2.13GHz
hw.ncpu: 1
hw.byteorder: 1234
hw.physmem: 2062254080
hw.usermem: 1860755456
hw.pagesize: 4096
hw.floatingpoint: 1
hw.machine_arch: i386
hw.platform: pc32
hw.aac.iosize_max: 65536
hw.cbb.start_memory: 2281701376
hw.cbb.start_16_io: 256
hw.cbb.start_32_io: 4096
hw.cbb.debug: 0
hw.cardbus.debug: 0
hw.cardbus.cis_debug: 0
hw.an.an_dump: off
hw.an.an_cache_mode: dbm
hw.an.an_cache_mcastonly: 0
hw.an.an_cache_iponly: 1
hw.ata.mpipe_size: 4
hw.ata.ata_dma: 1
hw.ata.wc: 1
hw.ata.tags: 0
hw.ata.atapi_dma: 0
hw.firewire.try_bmr: 1
hw.firewire.hold_count: 3
hw.firewire.fwmem.eui64_hi: 0
hw.firewire.fwmem.eui64_lo: 0
hw.firewire.fwmem.speed: 2
hw.firewire.fwe.stream_ch: 1
hw.firewire.fwe.tx_speed: 2
hw.firewire.fwe.rx_queue_len: 128
hw.firewire.sbp.auto_login: 1
hw.firewire.sbp.max_speed: -1
hw.firewire.sbp.exclusive_login: 1
hw.firewire.sbp.login_delay: 1000
hw.firewire.sbp.scan_delay: 500
hw.firewire.sbp.tags: 0
hw.fxp_rnr: 0
hw.wi.txerate: 0
hw.wi.debug: 0
hw.rtw.rfprog_fallback: 0
hw.rtw.host_rfio: 0
hw.rtw.chip_reset: 0
hw.xe.debug: 1
hw.pccard.debug: 0
hw.pccard.cis_debug: 0
hw.dc_quick: 1
hw.usb.ugen.bufsize: 16384
hw.instruction_sse: 1
hw.availpages: 503514
hw.i8254.freq: 1193182
hw.i8254.timestamp: 00000000 00151b77cbbffe68
hw.pci_disable_bios_route: 0
hw.acpi.supported_sleep_state: S3 S4 S5
hw.acpi.power_button_state: S5
hw.acpi.sleep_button_state: S3
hw.acpi.lid_switch_state: NONE
hw.acpi.standby_state: S1
hw.acpi.suspend_state: S3
hw.acpi.sleep_delay: 1
hw.acpi.s4bios: 0
hw.acpi.verbose: 0
hw.acpi.disable_on_poweroff: 0
hw.acpi.reset_video: 1
hw.acpi.cpu.throttle_max: 8
hw.acpi.cpu.throttle_state: 8
hw.acpi.cpu.performance_speed: 8
hw.acpi.cpu.economy_speed: 4
hw.acpi.cpu.cx_supported: C1/0
hw.acpi.cpu.cx_lowest: C1
hw.acpi.cpu.cx_usage: 100.00%
hw.twe0.driver_version: 1.40.01.002
hw.em0.debug_info: -1
hw.em0.stats: -1
hw.em0.rx_int_delay: 0
hw.em0.tx_int_delay: 66
hw.em0.rx_abs_int_delay: 66
hw.em0.tx_abs_int_delay: 66
hw.em0.int_throttle_ceil: 10000
hw.fxp0.int_delay: 1000
hw.fxp0.bundle_max: 6
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