GNU bug report logs - #35069
runtest takes too long on get_local_hostname

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Package: dejagnu;

Reported by: Tom de Vries <tdevries <at> suse.de>

Date: Mon, 1 Apr 2019 10:06:01 UTC

Severity: normal

Done: jcb62281 <at> gmail.com

Bug is archived. No further changes may be made.

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Report forwarded to bug-dejagnu <at> gnu.org:
bug#35069; Package dejagnu. (Mon, 01 Apr 2019 10:06:02 GMT) Full text and rfc822 format available.

Acknowledgement sent to Tom de Vries <tdevries <at> suse.de>:
New bug report received and forwarded. Copy sent to bug-dejagnu <at> gnu.org. (Mon, 01 Apr 2019 10:06:02 GMT) Full text and rfc822 format available.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Tom de Vries <tdevries <at> suse.de>
To: bug-dejagnu <at> gnu.org
Subject: runtest takes too long on get_local_hostname
Date: Mon, 1 Apr 2019 12:05:50 +0200
Hi,

I've setup a dejagnu testsuite for the dwz component (
https://sourceware.org/git/?p=dwz.git;a=summary ).

I'm running into the following problem.

Usually the testsuite runs in 12 seconds, but sometimes it takes more
than a minute (I managed to reproduce the same problem by running a
single gcc testsuite test-case).

I tracked this down to tcl info hostname taking a long time, when:
- having a vpn session active, and
- having no network connection

I manage to work around this by editing /usr/share/dejagnu/runtest.exp
and redefining get_local_hostname like this:
...
proc get_local_hostname { } {
    return [exec hostname]
}
...

I think it's a bug that a testsuite run that tests no network
functionality slows down by a factor of 5 when there's no network
connection.

[ In absence of a fix, I would already be grateful if somebody can point
out to me how I can work around this in a site.exp or board file or some
such, I tried myself but didn't manage to make that work. ]

Thanks,
- Tom




Information forwarded to bug-dejagnu <at> gnu.org:
bug#35069; Package dejagnu. (Mon, 01 Apr 2019 13:40:02 GMT) Full text and rfc822 format available.

Message #8 received at 35069 <at> debbugs.gnu.org (full text, mbox):

From: Andreas Schwab <schwab <at> suse.de>
To: Tom de Vries <tdevries <at> suse.de>
Cc: 35069 <at> debbugs.gnu.org
Subject: Re: bug#35069: runtest takes too long on get_local_hostname
Date: Mon, 01 Apr 2019 15:39:17 +0200
On Apr 01 2019, Tom de Vries <tdevries <at> suse.de> wrote:

> Usually the testsuite runs in 12 seconds, but sometimes it takes more
> than a minute (I managed to reproduce the same problem by running a
> single gcc testsuite test-case).
>
> I tracked this down to tcl info hostname taking a long time, when:
> - having a vpn session active, and
> - having no network connection

Tcl calls gethostbyname on your hostname, so you should make sure that
it is resolvable (by adding it to /etc/hosts, for example, or installing
nss-myhostname).  That's probably a good idea anyway, since there may be
other programs trying to do that too.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab <at> suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."




Information forwarded to bug-dejagnu <at> gnu.org:
bug#35069; Package dejagnu. (Mon, 01 Apr 2019 14:56:01 GMT) Full text and rfc822 format available.

Message #11 received at 35069 <at> debbugs.gnu.org (full text, mbox):

From: Tom de Vries <tdevries <at> suse.de>
To: Andreas Schwab <schwab <at> suse.de>
Cc: 35069 <at> debbugs.gnu.org
Subject: Re: bug#35069: runtest takes too long on get_local_hostname
Date: Mon, 1 Apr 2019 15:55:59 +0200
On 01-04-19 15:39, Andreas Schwab wrote:
> On Apr 01 2019, Tom de Vries <tdevries <at> suse.de> wrote:
> 
>> Usually the testsuite runs in 12 seconds, but sometimes it takes more
>> than a minute (I managed to reproduce the same problem by running a
>> single gcc testsuite test-case).
>>
>> I tracked this down to tcl info hostname taking a long time, when:
>> - having a vpn session active, and
>> - having no network connection
> 
> Tcl calls gethostbyname on your hostname, so you should make sure that
> it is resolvable (by adding it to /etc/hosts, for example, or installing
> nss-myhostname).  That's probably a good idea anyway, since there may be
> other programs trying to do that too.

Hi,

that works for me, thanks.

FTR, I do consider this a workaround though. If my internet connection
or configuration is broken in some way, I still expect say, ls to work
reliably, with the same speed. And I would expect the same for dejagnu
runtest (unless I would be testing network functionality, or remote
boards or some such).

Thanks,
- Tom




Information forwarded to bug-dejagnu <at> gnu.org:
bug#35069; Package dejagnu. (Mon, 01 Apr 2019 15:15:01 GMT) Full text and rfc822 format available.

Message #14 received at 35069 <at> debbugs.gnu.org (full text, mbox):

From: Andreas Schwab <schwab <at> suse.de>
To: Tom de Vries <tdevries <at> suse.de>
Cc: 35069 <at> debbugs.gnu.org
Subject: Re: bug#35069: runtest takes too long on get_local_hostname
Date: Mon, 01 Apr 2019 17:14:10 +0200
On Apr 01 2019, Tom de Vries <tdevries <at> suse.de> wrote:

> FTR, I do consider this a workaround though. If my internet connection
> or configuration is broken in some way, I still expect say, ls to work
> reliably, with the same speed.

If ls needs to contact an LDAP server to resolve user names you cannot
expect it to work well when your LDAP server doesn't answer.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab <at> suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."




Information forwarded to bug-dejagnu <at> gnu.org:
bug#35069; Package dejagnu. (Mon, 01 Apr 2019 20:42:01 GMT) Full text and rfc822 format available.

Message #17 received at 35069 <at> debbugs.gnu.org (full text, mbox):

From: Rob Savoye <rob <at> senecass.com>
Cc: 35069 <at> debbugs.gnu.org
Subject: Re: bug#35069: runtest takes too long on get_local_hostname
Date: Mon, 1 Apr 2019 08:36:41 -0600
On 4/1/19 7:39 AM, Andreas Schwab wrote:

> Tcl calls gethostbyname on your hostname, so you should make sure that
> it is resolvable (by adding it to /etc/hosts, for example, or installing
> nss-myhostname).  That's probably a good idea anyway, since there may be
> other programs trying to do that too.

  I thought everybody did that. :-) Which is probably why nobody noticed
the latency... All the machines in my build farm have entries in /etc/hosts.

	- rob -




Information forwarded to bug-dejagnu <at> gnu.org:
bug#35069; Package dejagnu. (Mon, 01 Apr 2019 22:29:02 GMT) Full text and rfc822 format available.

Message #20 received at 35069 <at> debbugs.gnu.org (full text, mbox):

From: Jacob Bachmeyer <jcb62281 <at> gmail.com>
To: Tom de Vries <tdevries <at> suse.de>
Cc: 35069 <at> debbugs.gnu.org, Andreas Schwab <schwab <at> suse.de>
Subject: Re: bug#35069: runtest takes too long on get_local_hostname
Date: Mon, 01 Apr 2019 17:28:04 -0500
Tom de Vries wrote:
> On 01-04-19 15:39, Andreas Schwab wrote:
>   
>> On Apr 01 2019, Tom de Vries <tdevries <at> suse.de> wrote:
>>     
>>> Usually the testsuite runs in 12 seconds, but sometimes it takes more
>>> than a minute (I managed to reproduce the same problem by running a
>>> single gcc testsuite test-case).
>>>
>>> I tracked this down to tcl info hostname taking a long time, when:
>>> - having a vpn session active, and
>>> - having no network connection
>>>       
>> Tcl calls gethostbyname on your hostname, so you should make sure that
>> it is resolvable (by adding it to /etc/hosts, for example, or installing
>> nss-myhostname).  That's probably a good idea anyway, since there may be
>> other programs trying to do that too.
>>     
> [...]
>
> FTR, I do consider this a workaround though. If my internet connection
> or configuration is broken in some way, I still expect say, ls to work
> reliably, with the same speed. And I would expect the same for dejagnu
> runtest (unless I would be testing network functionality, or remote
> boards or some such).
>   

I argue that this issue is an NSS configuration error rather than a bug 
in DejaGnu or even Tcl.  The issue seems to be that you had a NSS 
configuration that exhibits extremely poor performance in the situation 
you describe.  The solution is, of course, to fix your NSS configuration 
-- there is nothing DejaGnu can really do about this.

To use your example, ls(1) can only be expected to work reliably and 
quickly when the network is down if the UID/username map is stored 
locally, as is traditionally done on non-networked systems.  In 
networked environments where that mapping is stored in a central server, 
it is accepted that network failure causes other problems.

I had always understood that /etc/hosts should map a machine's own 
hostname to loopback and that omitting that record is a configuration error.

-- Jacob




Information forwarded to bug-dejagnu <at> gnu.org:
bug#35069; Package dejagnu. (Mon, 25 May 2020 16:20:02 GMT) Full text and rfc822 format available.

Message #23 received at 35069 <at> debbugs.gnu.org (full text, mbox):

From: Rob Savoye <rob <at> welcomehome.org>
To: 35069 <at> debbugs.gnu.org
Subject: bug#35069
Date: Mon, 25 May 2020 10:12:06 -0600
> I had always understood that /etc/hosts should map a machine's own
> hostname to loopback and that omitting that record is a configuration
> error.

  Interesting, I've never heard that, but I think at this point it's
more of a documentation issue that entries should be in /etc/hosts, more
than a bug.

	- rob -




Information forwarded to bug-dejagnu <at> gnu.org:
bug#35069; Package dejagnu. (Mon, 25 May 2020 16:20:02 GMT) Full text and rfc822 format available.

Message #26 received at 35069 <at> debbugs.gnu.org (full text, mbox):

From: Rob Savoye <rob <at> welcomehome.org>
To: 35069 <at> debbugs.gnu.org
Subject: bug#35069
Date: Mon, 25 May 2020 10:14:47 -0600
close 35069




bug closed, send any further explanations to 35069 <at> debbugs.gnu.org and Tom de Vries <tdevries <at> suse.de> Request was from Jacob Bachmeyer <jcb62281 <at> gmail.com> to control <at> debbugs.gnu.org. (Tue, 26 May 2020 04:37:01 GMT) Full text and rfc822 format available.

bug archived. Request was from Debbugs Internal Request <help-debbugs <at> gnu.org> to internal_control <at> debbugs.gnu.org. (Tue, 23 Jun 2020 11:24:06 GMT) Full text and rfc822 format available.

This bug report was last modified 3 years and 279 days ago.

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