| Summary: | there is no packet longer than MTU when tso is on (e1000) | ||||||
|---|---|---|---|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Siyuan Wang <siywang> | ||||
| Component: | qemu-kvm | Assignee: | Virtualization Maintenance <virt-maint> | ||||
| Status: | CLOSED NOTABUG | QA Contact: | Virtualization Bugs <virt-bugs> | ||||
| Severity: | medium | Docs Contact: | |||||
| Priority: | unspecified | ||||||
| Version: | 6.3 | CC: | acathrow, akong, bsarathy, jasowang, juzhang, mkenneth, virt-maint | ||||
| Target Milestone: | rc | ||||||
| Target Release: | --- | ||||||
| Hardware: | Unspecified | ||||||
| OS: | Unspecified | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2012-01-05 07:25:41 UTC | Type: | --- | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Attachments: |
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(In reply to comment #0) > Created attachment 550811 [details] > this file is generated by cmd "tcpdump -i switch -w > host62_guest62_e1000_tso_on.dump" > > Description of problem: > there is no packet longer than MTU when tso is on in e1000 > > Version-Release number of selected component (if applicable): > qemu-kvm-0.12.1.2-2.213.el6.x86_64 > > How reproducible: > 100% > > Steps to Reproduce: > 1. boot a guest with e1000 nic and open tso on guest: > ethtool -K eth0 tso on > > 2. scp from guest to host > > 3. use tcpdump to capture the packets on host > tcpdump -i switch -w host62_guest62_e1000_tso_on.dump > > 4. analyze the result, there is no packet longer than MTU > wireshark host62_guest62_e1000_tso_on.dump > > Actual results: > there is no packet longer than MTU > > Expected results: > there are packets longer than MTU This is not the expected result, you can not get a packet larger than MTU even for a real e1000 card. The reason why virtio can is that it passes GSO packet to host directly. > > Additional info: > > 1. virtio nic > rhel6.2 guest --> pass > > 2. e1000 nic > rhel6.2 guest --> Failed (In reply to comment #2) > (In reply to comment #0) > > Created attachment 550811 [details] > > this file is generated by cmd "tcpdump -i switch -w > > host62_guest62_e1000_tso_on.dump" > > > > Description of problem: > > there is no packet longer than MTU when tso is on in e1000 > > > > Version-Release number of selected component (if applicable): > > qemu-kvm-0.12.1.2-2.213.el6.x86_64 > > > > How reproducible: > > 100% > > > > Steps to Reproduce: > > 1. boot a guest with e1000 nic and open tso on guest: > > ethtool -K eth0 tso on > > > > 2. scp from guest to host > > > > 3. use tcpdump to capture the packets on host > > tcpdump -i switch -w host62_guest62_e1000_tso_on.dump Hi siyuan, | autotest/client/tests/ethtool.py :(+125) | logging.debug("Listen using command: %s", tcpdump_cmd) | session2.sendline(tcpdump_cmd) ^^^^^^^ tcpdump is executed in guest, large packets would be cut by emulated e1000 nic (not guest protocol layer, TSO is enabled). | if not virt_utils.wait_for( | lambda:session.cmd_status("pgrep tcpdump") == 0, 30): Please try to capture packets in guest. I can capture large packets in guest, so it's not a bug. |
Created attachment 550811 [details] this file is generated by cmd "tcpdump -i switch -w host62_guest62_e1000_tso_on.dump" Description of problem: there is no packet longer than MTU when tso is on in e1000 Version-Release number of selected component (if applicable): qemu-kvm-0.12.1.2-2.213.el6.x86_64 How reproducible: 100% Steps to Reproduce: 1. boot a guest with e1000 nic and open tso on guest: ethtool -K eth0 tso on 2. scp from guest to host 3. use tcpdump to capture the packets on host tcpdump -i switch -w host62_guest62_e1000_tso_on.dump 4. analyze the result, there is no packet longer than MTU wireshark host62_guest62_e1000_tso_on.dump Actual results: there is no packet longer than MTU Expected results: there are packets longer than MTU Additional info: 1. virtio nic rhel6.2 guest --> pass 2. e1000 nic rhel6.2 guest --> Failed