Bug 10618

Summary: boot_delay too slow
Product: Timers Reporter: Dave Young (hidave.darkstar)
Component: OtherAssignee: john stultz (john.stultz)
Status: CLOSED OBSOLETE    
Severity: normal CC: alan, bunk, hidave.darkstar, rdunlap
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 2.6.23 and above Subsystem:
Regression: No Bisected commit-id:

Description Dave Young 2008-05-07 19:00:30 UTC 
Latest working kernel version: not sure
Earliest failing kernel version: not sure
Distribution: slackware
Hardware Environment: i386
Software Environment:
Problem Description: boot_delay with more than 10ms is too slow, even 10ms it's very slow as well.

Steps to reproduce: lpj=your_lpj_copy_from_last_dmesg boot_delay=100ms
Comment 1 Dave Young 2008-05-07 19:07:52 UTC 
There's some discussion about it in lkml. I feel like it's related to x86 timers, but not sure. 

Use mdelay the result is more acceptable, but mdelay seems work only after the delay caliberation.

OTOH, I found printk_time is about 3 * boot_delay while testing. But the real time interval is far longer then 3 * boot_delay.

BTW, I tested on my powerpc g4 macmini, boot_delay works ok.