time reports incorrect max rss

Bug #742248 reported by Dejan Jovanović on 2011-03-25
This bug affects 6 people
Affects Status Importance Assigned to Milestone
time (Debian)
Fix Released
time (Fedora)
Fix Released
time (Ubuntu)

Bug Description

Binary package hint: time

rusage reports max rss and other memory information in KB and time assumes it is in number of pages, so it multiplies it with 4, resulting in inflated max rss

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: time 1.7-23ubuntu1
ProcVersionSignature: Ubuntu 2.6.35-28.49-generic
Uname: Linux 2.6.35-28-generic i686
NonfreeKernelModules: wl
Architecture: i386
Date: Fri Mar 25 00:38:03 2011
InstallationMedia: Ubuntu-Netbook 10.04 "Lucid Lynx" - Release i386 (20100429.4)
 PATH=(custom, user)
SourcePackage: time

Dejan Jovanović (dddejan) wrote :

Description of problem:

GNU time can print out the maximum RSS usage of its subprocess. The ru_maxrss value returned by the wait4 syscall is in units of kilobytes, but GNU time incorrectly treats this as a number of pages, multiplying the value by 4 before displaying it.

Version-Release number of selected component (if applicable):

How reproducible: Always

Steps to Reproduce:
1. /usr/bin/time -f %M perl -e '"x" x 400 x 1024 x 1024'

Actual results: A bit over 1600000, indicating maximum RSS usage of 1.6 GB. This is not even possible on my system as it only has 1 GB of physical RAM.

Expected results: Approximately 400000, since Perl should only be allocating around 400 MB.

Additional info:

Applying strace to the above command, it is clear that time is multiplying the ru_maxrss value returned by wait4:

$ strace -ve wait4 /usr/bin/time -f %M perl -e '"x" x 400 x 1024 x 1024'
wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, {ru_utime={0, 146977}, ru_stime={0, 676897}, ru_maxrss=411356, ru_ixrss=0, ru_idrss=0, ru_isrss=0, ru_minflt=102901, ru_majflt=1, ru_nswap=0, ru_inblock=176, ru_oublock=0, ru_msgsnd=0, ru_msgrcv=0, ru_nsignals=0, ru_nvcsw=1, ru_nivcsw=40}) = 7459
--- {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=7459, si_status=0, si_utime=14, si_stime=68} (Child exited) ---

According to the getrusage(2) manpage:

  ru_maxrss (since Linux 2.6.32)
     This is the maximum resident set size used (in kilobytes). [...]

I've attached a simple patch that simply skips the "pages to kilobytes" conversion for this field.

Created attachment 497533
Do not incorrectly convert ru_maxrss

smlx (sml) wrote :

There's a patch on the fedora bugzilla for this issue:

Changed in time (Ubuntu):
status: New → Confirmed

All Fedoras affected (time-1.7).

Thank you for the report, fixed time version will be pushed into Fedoras soon.

Fixed in time-1.7-39.fc16 for F16.

time-1.7-39.fc15 has been submitted as an update for Fedora 15.

time-1.7-38.fc14 has been submitted as an update for Fedora 14.

time-1.7-38.fc13 has been submitted as an update for Fedora 13.

Package time-1.7-38.fc14:
* should fix your issue,
* was pushed to the Fedora 14 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing time-1.7-38.fc14'
as soon as you are able to.
Please go to the following url:
then log in and leave karma (feedback).

time-1.7-39.fc15 has been pushed to the Fedora 15 stable repository. If problems still persist, please make note of it in this bug report.

time-1.7-38.fc14 has been pushed to the Fedora 14 stable repository. If problems still persist, please make note of it in this bug report.

time-1.7-38.fc13 has been pushed to the Fedora 13 stable repository. If problems still persist, please make note of it in this bug report.

Peter Bašista (pbasista) wrote :

Attaching a patch to the oneiric version of package time.

Changed in time (Ubuntu):
status: Confirmed → In Progress

The attachment "time.patch" of this bug report has been identified as being a patch. The ubuntu-reviewers team has been subscribed to the bug report so that they can review the patch. In the event that this is in fact not a patch you can resolve this situation by removing the tag 'patch' from the bug report and editing the attachment so that it is not flagged as a patch. Additionally, if you are member of the ubuntu-sponsors please also unsubscribe the team from this bug report.

[This is an automated message performed by a Launchpad user owned by Brian Murray. Please contact him regarding any issues with the action taken in this bug report.]

tags: added: patch
Peter Bašista (pbasista) wrote :


Is anybody watching this?

I can not commit the attached patch myself, so ...
Can I ask someone who can, ... would you be that kind and do that, please?
Thank you!

Changed in time (Ubuntu):
status: In Progress → Incomplete
Dejan Jovanović (dddejan) wrote :

What is the way ahead with this. I submitted the bug a year ago, and it's lame that nobody except Peter cares about it. Is there something I can do to speed it up?

Changed in time (Debian):
status: Unknown → New
Changed in time (Debian):
status: New → Fix Released
Changed in time (Fedora):
importance: Unknown → Undecided
status: Unknown → Fix Released
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