I am back from my visit at a customer where I installed a new and shiny gentoo server for running VMs (KVM).
Currently I don't have access as my VPN only works from my static IP at home (my router seems to be offline right now ... and I am still away from office for the weekend) so I can't check details now ... basically: I tried to copy/rsync some file with ~8GB over a gigabit connection ... from old to new server. Checked ethtool for gigabit, looked ok. I always saw the behavior that the transfer started rather fast and slowed down within minutes. Let's say ~50 MB/s in the start and then down to maybe 2 or so. That is way from the expected throughput with such new hardware. The NICs in the new server are BCM-something, Broadcom, using the tg3 Tigon module (exact model not available right now as mentioned above). In "dmesg" I see lines like hpet1: lost 1 rtc interrupts which makes me wonder if that leads to the lousy performance (btw, I fear slow virtualization performance as well). Dealing with HPET I checked for kernel support and also added kernel options to GRUB: hpet=force clocksource=hpet which lead to # cat /sys/devices/system/clocksource/clocksource0/current_clocksource hpet I am unsure if I should further investigate things around this HPET-issue? My thinkpad here shows "tsc" as clocksource ... good/better ? What direction to go? force or disable HPET? - btw I saw the same slowdown on 2 NICs: one connects the server to the LAN via GB-switch, the other connects the 2 servers directly via crossconnect-cable (dedicated for backups). I tried rsync with various options, scp, and even some tar/netcat-combo ... The system runs gentoo sources 3.10.7, amd64 ... - Thanks for any thoughts on this! Stefan
