Bug 80709 - HTB packet scheduler works incorectly with HZ other than 100 or 1024
Summary: HTB packet scheduler works incorectly with HZ other than 100 or 1024
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Linux
Classification: Retired
Component: kernel
Version: 7.3
Hardware: i386
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Arjan van de Ven
QA Contact: Brian Brock
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2002-12-30 07:48 UTC by Mindaugas Riauba
Modified: 2007-04-18 16:49 UTC (History)
0 users

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2003-06-07 19:40:02 UTC
Embargoed:

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Description Mindaugas Riauba 2002-12-30 07:48:58 UTC 
Description of problem:
HTB packet scheduler works not correctly when HZ is other than 100
or 1024. RedHat's default is 512. And problem appears only with
UDP traffic. TCP is shaped OK.

Version-Release number of selected component (if applicable):
kernel-smp-2.4.18-18.7.x

How reproducible:
100%

Steps to Reproduce:
1. Setup traffic shaping with HTB class.
2. Flood link with UDP traffic.
    
Actual results:
Traffic exceeds set limit or even is not shaped at all.

Expected results:
Shaped traffic.

Additional info:
At least in include/net/pkt_sched.h there is the following code:

#if HZ == 100
#define PSCHED_JSCALE 13
#elif HZ == 1024
#define PSCHED_JSCALE 10
#else
#define PSCHED_JSCALE 0
#endif
Comment 1 Arjan van de Ven 2003-06-07 19:40:02 UTC 
ought to be fixed in current erratum
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