Bug 1004416

Summary: time does not show really consumed time
Product: Red Hat Enterprise Linux 6 Reporter: Jan Ščotka <jscotka>
Component: timeAssignee: Petr Pisar <ppisar>
Status: CLOSED WONTFIX QA Contact: BaseOS QE - Apps <qe-baseos-apps>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 6.4CC: bnater, jscotka, psabata
Target Milestone: rcKeywords: FastFix, Patch
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
URL: http://lists.gnu.org/archive/html/bug-gnu-utils/2013-09/msg00003.html
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Fixed In Version: Doc Type: No Doc Update
Doc Text:
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Clone Of:
: 1005807 1412149 (view as bug list) Environment:
Last Closed: 2017-12-06 10:44:27 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description Flags
Test case
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Proposed fix none

Description Jan Ščotka 2013-09-04 15:07:15 UTC 
Description of problem:
Hi, then problem is based on
https://bugzilla.redhat.com/show_bug.cgi?id=960570
I've tried to use time to measure problem, but time itself is not able to deal with time shift and show incorrent result



How reproducible:
100%

Steps to Reproduce:
# CONST=70
# W=3
# time sleep $CONST& 
# BPID=$!
# sleep $W
# DOLD=`date`
# date -s "now - 1 minute"
# wait $BPID
# date -s "now + 1 minute"
# DNEW=`date`
# let DIFF=(`date +%s -d "$DNEW"` - `date +%s -d "$DOLD"`)
# echo $(($DIFF+$W)) == $CONST

Actual results:
time difference is 70 sec 
but time show:
real	0m10.001s
user	0m0.000s
sys	0m0.001s


Expected results:
real	1m10.001s

   Thanks&Regards
   Honza
Comment 2 Petr Šabata 2013-09-04 15:20:13 UTC 
Judging from the output, you seem to be using your shell's `time', not the `/usr/bin/time' binary.
Comment 3 Petr Pisar 2013-09-09 12:24:20 UTC 
Despite you use built-in `time', there is the same problem with GNU time.

I also think that time should measure monotonic (-alike) time not to get influenced by shifts in system clock.

clock_gettime(2) offers:

CLOCK_MONOTONIC -- suffers from NTP time adjustment.
CLOCK_MONOTONIC_RAW -- uses real hardware clock, I worry about precision and access permission for non-root users.
CLOCK_BOOTTIME -- includes time elapsed in suspension but suffers from NTP time adjustment. Is it worth?

I guess the CLOCK_MONOTONIC_RAW is the most appropriate.
Comment 4 Petr Pisar 2013-09-09 12:24:52 UTC 
Created attachment 795594 [details]
Test case
Comment 8 Petr Pisar 2014-10-21 13:15:50 UTC 
Upstream agreed to use clock_gettime(CLOCK_MONOTONIC) for measuring the "real" value.
Comment 11 Petr Pisar 2016-11-30 17:08:10 UTC 
Created attachment 1226439 [details]
Proposed fix
Comment 12 Petr Pisar 2017-01-11 10:17:18 UTC 
Patches posted to upstream <http://lists.gnu.org/archive/html/bug-gnu-utils/2016-12/msg00000.html>, but upstream seems dead.
Comment 13 Petr Pisar 2017-01-11 14:27:03 UTC 
Created attachment 1239457 [details]
Proposed fix
Comment 14 Jan Kurik 2017-12-06 10:44:27 UTC 
Red Hat Enterprise Linux 6 is in the Production 3 Phase. During the Production 3 Phase, Critical impact Security Advisories (RHSAs) and selected Urgent Priority Bug Fix Advisories (RHBAs) may be released as they become available.

The official life cycle policy can be reviewed here:

http://redhat.com/rhel/lifecycle

This issue does not meet the inclusion criteria for the Production 3 Phase and will be marked as CLOSED/WONTFIX. If this remains a critical requirement, please contact Red Hat Customer Support to request a re-evaluation of the issue, citing a clear business justification. Note that a strong business justification will be required for re-evaluation. Red Hat Customer Support can be contacted via the Red Hat Customer Portal at the following URL:

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