Bug 1549 - hwclock --systohc can take 25 seconds
Summary: hwclock --systohc can take 25 seconds
Status: RESOLVED FIXED
Alias: None
Product: Busybox
Classification: Unclassified
Component: Other (show other bugs)
Version: 1.16.x
Hardware: PC Linux
: P5 normal
Target Milestone: ---
Assignee: unassigned
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2010-04-14 10:53 UTC by Ivo Clarysse
Modified: 2010-04-17 06:09 UTC (History)
1 user (show)

See Also:
Host: GNU/Linux 2.6 x86
Target: GNU/Linux 2.4 ARM / i.MX21
Build: 1.16.1

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Description Ivo Clarysse 2010-04-14 10:53:57 UTC 
Since busybox 1.6.0, "hwclock --systohc" takes 25 seconds to complete on a Freescale i.MX21 (an ARM-based SoC) running at 266MHz.

This is due to the ""2010-01-06 hwclock: fix sizeof bug (used it on pointer, not array); make --systohc exact" change introduced in busybox 1.16.0.

Changing TWEAK_USEC from 200 to 1000 brought this time down again to less than 0.1 second.

By default TWEAK_USEC appears to be tuned for a 2.2GHz Intel Core 2. It would appear that when building for a typical embedded device, busybox must be patched to have 'hwclock --systohc' complete in an acceptable timespan.
Comment 1 Ivo Clarysse 2010-04-14 10:56:48 UTC 
Correction: Since busybox 1.6.0 -> Since busybox 1.16.0