|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-users] ntpd under Xen Dom0 exhibits extremely high jitter/noise? runs stable/quiet under non-xen kernel.
On Thu, Jan 14, 2010 at 8:20 PM, Fajar A. Nugraha <fajar@xxxxxxxxx> wrote: >> @ novell say it's xen & ntp >> @ ntp say it's novell & xen >> @ xen say it's novell & ntp >> > That's why I suggested you use a workaround: use 2.6.18 kernel, either > from RHEL or from xen.org :D > If this works -> novell problem > If this doesn't work -> xen problem On Sat, Jan 16, 2010 at 5:05 AM, Fajar A. Nugraha <fajar@xxxxxxxxx> wrote: > You might want to try latest pv_ops as well > (http://wiki.xensource.com/xenwiki/XenParavirtOps), which should be > easier to work with Opensuse since the version number is close. it seems it's _not_ the kernel -- unless there's a coincident kernel problem across source/vendor ... per http://lists.xensource.com/archives/html/xen-devel/2009-12/msg01127.html http://wiki.xensource.com/xenwiki/XenParavirtOps http://wiki.xensource.com/xenwiki/Kernel.org_Linux_on_Xen cd /home/workspace && rm -rf linux-2.6-xen git clone git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git linux-2.6-xen cd linux-2.6-xen make clean cp -a .config .config-old wget -O .config http://pasik.reaktio.net/xen/pv_ops-dom0-debug/config-2.6.31.4-pvops_dom0-x86_64 make oldconfig ... Xen PCI Frontend (XEN_PCIDEV_FRONTEND) [N/m/y/?] (NEW) <-- m ... "IMQ" target support (NETFILTER_XT_TARGET_IMQ) [N/m/?] (NEW) <-- m ... IMQ (intermediate queueing device) support (IMQ) [M/y/?] (NEW) <-- [enter] ... Block-device tap backend driver (XEN_BLKDEV_TAP) [N/m/y/?] (NEW) <-- m ... make bzImage make modules make modules_install strip vmlinux -o vmlinux-stripped gzip vmlinux-stripped -c > vmlinuz-gzipped ls -al .config \ System.map \ arch/x86/boot/bzImage \ vmlinux \ vmlinux-stripped \ vmlinuz-gzipped cp -a .config /boot/config-2.6.31.6 cp -a System.map /boot/System.map-2.6.31.6 cp -a arch/x86/boot/bzImage /boot/vmlinuz-2.6.31.6 mkinitrd ls -al /boot/*2.6.31.6* -rw-r--r-- 1 root root 98510 2010-01-16 03:02 /boot/config-2.6.31.6 -rw-r--r-- 1 root root 21304611 2010-01-16 04:14 /boot/initrd-2.6.31.6 -rw-r--r-- 1 root root 1940879 2010-01-16 03:14 /boot/System.map-2.6.31.6 -rw-r--r-- 1 root root 3751936 2010-01-16 03:14 /boot/vmlinuz-2.6.31.6 vi /boot/grub/menu.lst ... title xen.git root (hd0,0) kernel /xen.gz loglvl=all loglvl_guest=all dom0_mem=1024M vga=gfx-1280x1024x32 console=vga,com1 com1=57600,8n1 module /vmlinuz-2.6.31.6 root=/dev/VG0/ROOT rootfstype=ext4 rootflags=journal_checksum resume=/dev/VG0/SWAP nomodeset selinux=0 SELINUX_INIT=NO vga=0x31a console=tty0 console=xvc0,57600 module /initrd-2.6.31.6 title xen.git DISABLED root (hd0,0) kernel /vmlinuz-2.6.31.6 root=/dev/VG_SVR/LV_SVR_DOM0_ROOT rootfstype=ext4 rootflags=journal_checksum resume=/dev/VG_SVR/LV_SVR_DOM0_SWAP nomodeset showopts splash=silent selinux=0 SELINUX_INIT=NO elevator=cfq vga=0x31a console=tty0 console=ttyS0,57600n8 module /initrd-2.6.31.6 ... boot to "xen.git" uname -a Linux test 2.6.31.6 #1 SMP Sat Jan 16 03:14:19 PST 2010 x86_64 x86_64 x86_64 GNU/Linux lsb_release -a LSB Version: core-2.0-noarch:core-3.2-noarch:core-4.0-noarch:core-2.0-x86_64:core-3.2-x86_64:core-4.0-x86_64:desktop-4.0-amd64:desktop-4.0-noarch:graphics-2.0-amd64:graphics-2.0-noarch:graphics-3.2-amd64:graphics-3.2-noarch:graphics-4.0-amd64:graphics-4.0-noarch Distributor ID: SUSE LINUX Description: openSUSE 11.2 (x86_64) Release: 11.2 Codename: n/a service ntp stop rm /etc/adjtime /var/ rm /var/lib/ntp/drift/ntp.drift cat << EOF > /etc/sysconfig/clock HWCLOCK="--utc" SYSTOHC="yes" TIMEZONE="America/Los_Angeles" DEFAULT_TIMEZONE="US/Pacific" EOF hwclock --systohc --utc service ntp start sntp clock.isc.org && date && hwclock --utc --show 2010 Jan 16 04:37:09.000729 + 1.435060 +/- 0.028944 secs Sat Jan 16 04:37:11 PST 2010 Sat 16 Jan 2010 04:37:11 AM PST -0.345191 seconds ... (wait ~ 6 hours) ... date Sat Jan 16 11:01:42 PST 2010 ntpq -p -c rv assID=0 status=06c4 leap_none, sync_ntp, 12 events, event_peer/strat_chg, version="ntpd 4.2.4p8@xxxxxx Mon Dec 28 17:26:30 UTC 2009 (1)", processor="x86_64", system="Linux/2.6.31.6", leap=00, stratum=2, precision=-20, rootdelay=14.718, rootdispersion=135.995, peer=11390, refid=66.220.9.122, reftime=cefc89b2.a36f1342 Sat, Jan 16 2010 10:53:38.638, poll=6, clock=cefc8b82.7e523feb Sat, Jan 16 2010 11:01:22.493, state=2, offset=-115.130, frequency=-500.000, jitter=464.242, noise=29.343, stability=154.680 remote refid st t when poll reach delay offset jitter ============================================================================== *clock.fmt.he.ne .PPS. 1 u 29 64 377 21.438 -811.68 462.837 +otc2.psu.edu 129.6.15.29 2 u 7 64 377 109.399 -850.99 470.522 +clock.isc.org .GPS. 1 u 7 64 377 21.440 -854.82 468.274 +clock.sjc.he.ne .CDMA. 1 u 49 64 377 16.889 -780.55 469.481 +zorro.sf-bay.or 216.218.254.202 2 u 59 64 377 20.366 -762.14 458.947 +nist1.aol-ca.tr .ACTS. 1 u 38 64 377 16.260 -795.87 463.170 boot to "xen.git DISABLED" uname -a Linux test 2.6.31.6 #1 SMP Sat Jan 16 09:14:19 PST 2010 x86_64 x86_64 x86_64 GNU/Linux service ntp stop rm /etc/adjtime /var/ rm /var/lib/ntp/drift/ntp.drift service ntp start ... (wait ~ 10 minutes) ... date Sat Jan 16 11:15:05 PST 2010 ntpq -p -c rv assID=0 status=0664 leap_none, sync_ntp, 6 events, event_peer/strat_chg, version="ntpd 4.2.4p8@xxxxxx Mon Dec 28 17:26:30 UTC 2009 (1)", processor="x86_64", system="Linux/2.6.31.6", leap=00, stratum=2, precision=-20, rootdelay=22.750, rootdispersion=975.184, peer=43091, refid=66.220.9.122, reftime=cefc8c7c.35ca466a Sat, Jan 16 2010 11:05:32.210, poll=6, clock=cefc8eb9.25103a1f Sat, Jan 16 2010 11:15:05.144, state=3, offset=27.534, frequency=0.000, jitter=6.740, noise=16.331, stability=0.000 remote refid st t when poll reach delay offset jitter ============================================================================== *clock.fmt.he.ne .PPS. 1 u 4 64 377 18.112 10.541 5.892 +otc2.psu.edu 147.84.59.145 2 u 64 64 377 101.103 12.106 8.621 +clock.isc.org .GPS. 1 u 57 64 377 14.990 4.830 9.622 +clock.sjc.he.ne .CDMA. 1 u 59 64 377 16.503 9.299 9.440 +zorro.sf-bay.or 216.218.254.202 2 u 56 64 377 22.212 6.323 11.031 +nist1.aol-ca.tr .ACTS. 1 u 60 64 377 17.076 14.316 9.260 in summary, kernel OS/distro xen timekeeping ------------------------------------- --------------- ------- ------------ opensuse kernel-default-2.6.31.8-0.1 opensuse 11.2 (n/a) OK opensuse kernel-default-2.6.32-41 opensuse 11.2 (n/a) OK opensuse kernel-xen-2.6.31.8-0.1 opensuse 11.2 3.4.x NOISY/FAIL opensuse kernel-xen-2.6.32-41 opensuse 11.2 3.4.x NOISY/FAIL opensuse kernel-xen-2.6.31.8-0.1 opensuse 11.2 4.0.x NOISY/FAIL opensuse kernel-xen-2.6.32-41 opensuse 11.2 4.0.x NOISY/FAIL xen.git kernel-2.6.31.6 (pvops Dom0) opensuse 11.2 4.0.x NOISY/FAIL xen.git kernel-2.6.31.6 opensuse 11.2 (n/a) OK i.e., 3 different kernel versions, from two different vendors, have low-noise/accurate timekeeping in NON-xen configs. boot any of those kernels with either v34x or v40x hypervisor in place, and timekeeping suffers from unusably excessive jitter & offset. _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |