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