Bug 128188
Summary: | Very slow network I/O with kernel 2.6.7-1.492 | ||
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Product: | [Fedora] Fedora | Reporter: | H.J. Lu <hongjiu.lu> |
Component: | kernel | Assignee: | Dave Jones <davej> |
Status: | CLOSED CURRENTRELEASE | QA Contact: | |
Severity: | high | Docs Contact: | |
Priority: | medium | ||
Version: | rawhide | CC: | davem, pfrields, wtogami |
Target Milestone: | --- | ||
Target Release: | --- | ||
Hardware: | i686 | ||
OS: | Linux | ||
Whiteboard: | |||
Fixed In Version: | Doc Type: | Bug Fix | |
Doc Text: | Story Points: | --- | |
Clone Of: | Environment: | ||
Last Closed: | 2004-11-27 04:42:09 UTC | Type: | --- |
Regression: | --- | Mount Type: | --- |
Documentation: | --- | CRM: | |
Verified Versions: | Category: | --- | |
oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
Cloudforms Team: | --- | Target Upstream Version: | |
Embargoed: |
Description
H.J. Lu
2004-07-19 20:32:45 UTC
It looks like maybe a networking issue. I will keep an eye on it. Network performance in 2.6.7-1.492 is very bad. ssh, cvs and bk are very slow from remote server. Another machine on the same network running 2.4.21-15.EL is OK. After I booted RHEL 3 U2 on the same machine where 2.6.7-1.492 + FC 2 gave me very poort network performance, my network performance went back to normal. Does .499 or later work better? What driver? .503 kernel seems OK. Saturday is my day to backup my Windows system to the Linux box, and vice versa. I started the backup from Windows this morning. Backup estimated that it would take 18 hours to move the 1.9GB from Windows to Linux via Samba. Usually, the estimate is about 43 minutes. I rebooted both boxes and got the same estimate. I then rebooted the Linux machine from kernel 2.6.7-1.494 to kernel 2.6.6-1.435. With the older kernel, the backup time was back to a bit more than 40 minutes. I don't see any difference in the report from ifconfig for either kernel. .509 kernel seems bad. Network very slow on some web pages (e.g., CBS Market Watch) on 2.6.7-1.494. Reverting back to a 2.6.6 kernel solves the problem Tested kernel 2.6.8 with same slow results. Running Dell D600 laptop. Solution found under bug 126626. Need to set a couple of values under ipv4 directory. See last post in the bug comments. # echo 0 > /proc/sys/net/ipv4/tcp_default_win_scale # echo 0 > /proc/sys/net/ipv4/tcp_moderate_rcvbuf It seems that the 2.6.7 kernel changed these values from those in 2.6.6, which resulted in the slowdown. There is some suspicion that the problem is not with the 2.6.7 kernel, but possibly with the Cisco firewalls that may not recognize (or handle) the tcp_default_win_scale=7 value in the 2.6.7 kernel. the latest 2.6.9 kernels should be behaving correctly now, without editing that sysctl. Please reopen if this isnt the case. |