Where is HPET ?

[saintjimmygd]

Hello.Our hosting server has an odd issue and i don't know if it's BIOS related or Linux related.

Server configuration:
-motherboard : http://www.supermicro.com/products/motherboard/QPI/5500/X8DTL-3.cfm
-2 x Intel Xeon e5620 2.4 Ghz
-24 Gb RAM
-CentOS with kernel-2.6.33.7-rt29 (also Debian in vps with the same kernel)
-BIOS settings :

• HPET ON
• ACPI ON
• APIC ACPI SCI IRQ Enabled
• ACP Version Feature - ACPI v3.0
  

CentOS command:

Quote:cat /sys/devices/system/clocksource/clocksource0/available_clocksource

Result:

Quote:tsc acpi_pm

Debian command:

Quote:cat /sys/devices/system/clocksource/clocksource0/available_clocksource

Result:

Quote:tsc acpi_pm

Question: Where is HPET ? TSC gives bad results in game hosting , big variations of fps....Back at home,with HPET and the same kernel settings i have super stable FPS,so what is happening ?

[Monk]

Did you compile the kernel without ACPI support? IIRC if you remove ACPI support from the kernel, HPET will not be listed. I think ACPI announces HPET support in the SRAT(or mdat) tables and the kernel installs handlers for it.

[BehaartesEtwas]

removing ACPI support from kernel would remove "acpi_pm" as a clocksource. HPET has it's own kernel kernel option which is probably disabled. it's in "device drivers" / "character devices".

[saintjimmygd]

Power Management is OK, HPET was enabled also :





Result :



Also,i typed:

Quote:find /proc/sys -name "hpet"

Result:

Quote:/proc/sys/dev/hpet

[Monk]

What does 'dmesg | egrep -i hpet' show?

The hpet devices seems to get created regardless if the chipset supports it or not (if characeter device has it enabled it will always create a device, it looks like)

Also, see what clocks are reg'd:

egrep Clock /proc/timer_list | uniq

[saintjimmygd]

[ dmesg | egrep -i hpet ] : doesn't show anything , while [ egrep Clock /proc/timer_list | uniq ] shows :

Quote:Clock Event Device: pit
Clock Event Device: lapic

[BehaartesEtwas]

can you give us the output of

Code:

grep -i hpet .config

in your kernel directory? there is another option that needs to be enabled, but I cannot find it in menuconfig. on my kernel this looks like:

Code:

css linux # grep -i hpet .config
CONFIG_HPET_TIMER=y
CONFIG_HPET_EMULATE_RTC=y
CONFIG_HPET=y
CONFIG_HPET_MMAP=y

I think there shouldn't be any "N"s or "M"s...

[saintjimmygd]

Result :

Quote:CONFIG_HPET_TIMER=y
CONFIG_HPET_EMULATE_RTC=y
CONFIG_HPET=y
CONFIG_HPET_MMAP=y

It seems everything is ok ... :|

[Monk]

Bummer. Looks like your timer interrupts are being services by the PIT and lapic. You could try adding hpet=force to your kernel boot parameters to check.. another option would be to see if there is a BIOS update for this board (it might fix it being announced/enabled)

[saintjimmygd]

2 weeks ago i added clocksource=hpet in menu.lst , but there was a huge decrease in performance,fps going down to 50 from 1000 ... Yes,there are bios updates on the main site of the motherboard,should i try an update ?

[dualcore1289]

Yes, you should always keep your drivers up to date.

[Peter_Pan123]

look in the bios > normally you can switch it on there. if not you cant switch it on because its not inside > perhaps look at monk bios update could help.

[saintjimmygd]

Well,i found the problem.Our HDD's don't have a SAS Controller.They can only be detected by Windows.During installation,Linux distros don't recognize them.So the datacenter team installed CentOS on a virtual machine on our servers.So probably that's why HPET isn't recognized.
Besides buying a SAS Controller,is there a Linux distro that can recognize those HDD's during installation ? So far,debian and centos (installed from original DVD's) don't work....Anybody had this problem ?

[BehaartesEtwas]

ah ok, running game servers inside a vserver isn't a good idea in any case...

I don't understand really what your configuration is. You have a SAS HDD with a SAS controller that is not recognized by Linux? Then what SAS controller do you have? Can you post the output of lspci (not inside a VM of course... boot from some Linux Live CD)?

[saintjimmygd]

HDD:

Quote:2 x HDD Fujitsu MBA3300RC, 300GB, 15000rpm, 16MB [MBA3300RC]

Code:

Fujitsu MBA3300RC 300GB 15000 RPM 16MB Cache Serial Attached SCSI (SAS) 3.5" Internal Hard Drive -Bare Drive

SAS Controller Card

Quote:not present