[gentoo-user] Re: events/0 at 100% when running rsync

[Lincoln Baxter]

On 1/1/06, Lincoln Baxter <lincoln.a.baxter@×××××.com> wrote:
[snip]
> I resently upgraded to an Athlon X2 dual core processor and mobo.
>
> Recompile Kernel (gentoo-sources) for SMP etc, and I have both an
> events/0 and an events/1 process running.
>
> When I rsync one file system to another, the events/0 process goes
> 100% cpu bound on cpu0.  And the system becomes unusable, until the
> rsync finishes.
>
> I have been googling for events/0 and rsync and %100 CPU and have
> found very few pointers to what might be up.
>
[snip]

It appears that events/N is the kernel scheduler process for each CPUs run queue

On the suspicion that it was being called too frequently in this
scenario, I changed my kernel config from

   CONFIG_HZ_1000=y
   CONFIG_HZ=1000

to:

   CONFIG_HZ_250=y
   CONFIG_HZ=250

The problem seems to be completely solved.  I am thinking that
rescheduling processes 1000 times a second per processor was way too
excessive.  (Kernel is configured for low latency).

Anyone care to confirm that this would account for the problem being
resolved? (or should I look at something else I changed -- other
things were changed but I doubt that they would account for this).

I did change CONFIG_IO_SCHED_* to M from Y.

Question: could this have effected this?  How does one determine which
IO_SCHED algorythm is used?

FYI... Here is the full diff of what I changed:

# diff -c .config .config.060101-1
*** .config     Sun Jan  1 15:46:54 2006
--- .config.060101-1    Sun Jan  1 15:38:33 2006
***************
*** 1,7 ****
  #
  # Automatically generated make config: don't edit
  # Linux kernel version: 2.6.14-gentoo-r5
! # Sun Jan  1 15:46:54 2006
  #
  CONFIG_X86=y
  CONFIG_SEMAPHORE_SLEEPERS=y
--- 1,7 ----
  #
  # Automatically generated make config: don't edit
  # Linux kernel version: 2.6.14-gentoo-r5
! # Sun Jan  1 01:33:48 2006
  #
  CONFIG_X86=y
  CONFIG_SEMAPHORE_SLEEPERS=y
***************
*** 113,119 ****
  CONFIG_HPET_TIMER=y
  CONFIG_HPET_EMULATE_RTC=y
  CONFIG_SMP=y
! CONFIG_NR_CPUS=2
  # CONFIG_SCHED_SMT is not set
  # CONFIG_PREEMPT_NONE is not set
  # CONFIG_PREEMPT_VOLUNTARY is not set
--- 113,119 ----
  CONFIG_HPET_TIMER=y
  CONFIG_HPET_EMULATE_RTC=y
  CONFIG_SMP=y
! CONFIG_NR_CPUS=4
  # CONFIG_SCHED_SMT is not set
  # CONFIG_PREEMPT_NONE is not set
  # CONFIG_PREEMPT_VOLUNTARY is not set
***************
*** 137,143 ****
  #
  # CONFIG_EDD is not set
  # CONFIG_DELL_RBU is not set
! # CONFIG_DCDBAS is not set
  # CONFIG_NOHIGHMEM is not set
  CONFIG_HIGHMEM4G=y
  # CONFIG_HIGHMEM64G is not set
--- 137,143 ----
  #
  # CONFIG_EDD is not set
  # CONFIG_DELL_RBU is not set
! CONFIG_DCDBAS=m
  # CONFIG_NOHIGHMEM is not set
  CONFIG_HIGHMEM4G=y
  # CONFIG_HIGHMEM64G is not set
***************
*** 157,165 ****
  # CONFIG_REGPARM is not set
  CONFIG_SECCOMP=y
  # CONFIG_HZ_100 is not set
! CONFIG_HZ_250=y
! # CONFIG_HZ_1000 is not set
! CONFIG_HZ=250
  CONFIG_PHYSICAL_START=0x100000
  # CONFIG_KEXEC is not set

--- 157,165 ----
  # CONFIG_REGPARM is not set
  CONFIG_SECCOMP=y
  # CONFIG_HZ_100 is not set
! # CONFIG_HZ_250 is not set
! CONFIG_HZ_1000=y
! CONFIG_HZ=1000
  CONFIG_PHYSICAL_START=0x100000
  # CONFIG_KEXEC is not set

***************
*** 265,271 ****
  #
  # PCI Hotplug Support
  #
! # CONFIG_HOTPLUG_PCI is not set

  #
  # Executable file formats
--- 265,278 ----
  #
  # PCI Hotplug Support
  #
! CONFIG_HOTPLUG_PCI=m
! # CONFIG_HOTPLUG_PCI_FAKE is not set
! # CONFIG_HOTPLUG_PCI_COMPAQ is not set
! # CONFIG_HOTPLUG_PCI_IBM is not set
! # CONFIG_HOTPLUG_PCI_ACPI is not set
! # CONFIG_HOTPLUG_PCI_CPCI is not set
! CONFIG_HOTPLUG_PCI_SHPC=m
! # CONFIG_HOTPLUG_PCI_SHPC_POLL_EVENT_MODE is not set

  #
  # Executable file formats
***************
*** 492,500 ****
  # IO Schedulers
  #
  CONFIG_IOSCHED_NOOP=y
! CONFIG_IOSCHED_AS=m
! CONFIG_IOSCHED_DEADLINE=m
! CONFIG_IOSCHED_CFQ=m
  CONFIG_ATA_OVER_ETH=m

  #
--- 499,507 ----
  # IO Schedulers
  #
  CONFIG_IOSCHED_NOOP=y
! CONFIG_IOSCHED_AS=y
! CONFIG_IOSCHED_DEADLINE=y
! CONFIG_IOSCHED_CFQ=y
  CONFIG_ATA_OVER_ETH=m

  #
***************
*** 940,946 ****
  # Watchdog Cards
  #
  # CONFIG_WATCHDOG is not set
! CONFIG_HW_RANDOM=y
  # CONFIG_NVRAM is not set
  CONFIG_RTC=y
  # CONFIG_DTLK is not set
--- 947,953 ----
  # Watchdog Cards
  #
  # CONFIG_WATCHDOG is not set
! CONFIG_HW_RANDOM=m
  # CONFIG_NVRAM is not set
  CONFIG_RTC=y
  # CONFIG_DTLK is not set
***************
*** 1099,1105 ****
  #
  # Multimedia devices
  #
! # CONFIG_VIDEO_DEV is not set

  #
  # Digital Video Broadcasting Devices
--- 1106,1156 ----
  #
  # Multimedia devices
  #
! CONFIG_VIDEO_DEV=y
!
! #
! # Video For Linux
! #
!
! #
! # Video Adapters
! #
! # CONFIG_VIDEO_BT848 is not set
! # CONFIG_VIDEO_PMS is not set
! # CONFIG_VIDEO_BWQCAM is not set
! # CONFIG_VIDEO_CQCAM is not set
! # CONFIG_VIDEO_W9966 is not set
! # CONFIG_VIDEO_CPIA is not set
! # CONFIG_VIDEO_SAA5246A is not set
! # CONFIG_VIDEO_SAA5249 is not set
! # CONFIG_TUNER_3036 is not set
! # CONFIG_VIDEO_STRADIS is not set
! # CONFIG_VIDEO_ZORAN is not set
! # CONFIG_VIDEO_SAA7134 is not set
! # CONFIG_VIDEO_MXB is not set
! # CONFIG_VIDEO_DPC is not set
! # CONFIG_VIDEO_HEXIUM_ORION is not set
! # CONFIG_VIDEO_HEXIUM_GEMINI is not set
! # CONFIG_VIDEO_CX88 is not set
! # CONFIG_VIDEO_OVCAMCHIP is not set
!
! #
! # Radio Adapters
! #
! # CONFIG_RADIO_CADET is not set
! # CONFIG_RADIO_RTRACK is not set
! # CONFIG_RADIO_RTRACK2 is not set
! # CONFIG_RADIO_AZTECH is not set
! # CONFIG_RADIO_GEMTEK is not set
! # CONFIG_RADIO_GEMTEK_PCI is not set
! # CONFIG_RADIO_MAXIRADIO is not set
! # CONFIG_RADIO_MAESTRO is not set
! # CONFIG_RADIO_SF16FMI is not set
! # CONFIG_RADIO_SF16FMR2 is not set
! # CONFIG_RADIO_TERRATEC is not set
! # CONFIG_RADIO_TRUST is not set
! # CONFIG_RADIO_TYPHOON is not set
! # CONFIG_RADIO_ZOLTRIX is not set

  #
  # Digital Video Broadcasting Devices
***************
*** 1211,1220 ****
--- 1262,1274 ----
  CONFIG_SND_SEQ_RTCTIMER_DEFAULT=y
  # CONFIG_SND_VERBOSE_PRINTK is not set
  # CONFIG_SND_DEBUG is not set
+ CONFIG_SND_GENERIC_DRIVER=y

  #
  # Generic devices
  #
+ CONFIG_SND_MPU401_UART=m
+ CONFIG_SND_OPL3_LIB=m
  # CONFIG_SND_DUMMY is not set
  # CONFIG_SND_VIRMIDI is not set
  # CONFIG_SND_MTPAV is not set
***************
*** 1242,1248 ****
  # CONFIG_SND_OPTI93X is not set
  # CONFIG_SND_SB8 is not set
  # CONFIG_SND_SB16 is not set
! # CONFIG_SND_SBAWE is not set
  # CONFIG_SND_WAVEFRONT is not set
  # CONFIG_SND_ALS100 is not set
  # CONFIG_SND_AZT2320 is not set
--- 1296,1303 ----
  # CONFIG_SND_OPTI93X is not set
  # CONFIG_SND_SB8 is not set
  # CONFIG_SND_SB16 is not set
! CONFIG_SND_SBAWE=m
! CONFIG_SND_SB16_CSP=y
  # CONFIG_SND_WAVEFRONT is not set
  # CONFIG_SND_ALS100 is not set
  # CONFIG_SND_AZT2320 is not set
***************
*** 1269,1275 ****
  # CONFIG_SND_CS4281 is not set
  CONFIG_SND_EMU10K1=m
  # CONFIG_SND_EMU10K1X is not set
! # CONFIG_SND_CA0106 is not set
  # CONFIG_SND_KORG1212 is not set
  # CONFIG_SND_MIXART is not set
  # CONFIG_SND_NM256 is not set
--- 1324,1330 ----
  # CONFIG_SND_CS4281 is not set
  CONFIG_SND_EMU10K1=m
  # CONFIG_SND_EMU10K1X is not set
! CONFIG_SND_CA0106=m
  # CONFIG_SND_KORG1212 is not set
  # CONFIG_SND_MIXART is not set
  # CONFIG_SND_NM256 is not set
***************
*** 1394,1403 ****
  # USB Multimedia devices
  #
  # CONFIG_USB_DABUSB is not set
!
! #
! # Video4Linux support is needed for USB Multimedia device support
! #

  #
  # USB Network Adapters
--- 1449,1463 ----
  # USB Multimedia devices
  #
  # CONFIG_USB_DABUSB is not set
! # CONFIG_USB_VICAM is not set
! # CONFIG_USB_DSBR is not set
! # CONFIG_USB_IBMCAM is not set
! # CONFIG_USB_KONICAWC is not set
! # CONFIG_USB_OV511 is not set
! # CONFIG_USB_SE401 is not set
! # CONFIG_USB_SN9C102 is not set
! # CONFIG_USB_STV680 is not set
! # CONFIG_USB_PWC is not set

  #
  # USB Network Adapters

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