RE: agent_check_and_process: select info
Is this issue being followed up? Is there at least a ticket submitted? From: sbazd...@hotmail.com To: net-snmp-users@lists.sourceforge.net Subject: RE: agent_check_and_process: select info Date: Wed, 16 Sep 2009 16:22:24 -0400 I agree. On an embedded system, there are applications that can't be simply rebooted. There has to be a way for net-snmp agent to recover from this. Date: Wed, 16 Sep 2009 08:32:48 +0200 Subject: Re: agent_check_and_process: select info From: bart.vanass...@gmail.com To: mike_ay...@tvworks.com CC: sbazd...@hotmail.com; net-snmp-users@lists.sourceforge.net On Tue, Sep 15, 2009 at 11:16 PM, Mike Ayers mike_ay...@tvworks.com wrote: Then reboot! Apps (any apps) should certainly be able to handle clock changes, forward or back, of a second or less, without blinking. Time zone changes are nice to have, but some things barf on those (I have a cell phone that can't grasp the concept of moving between time zones). Forward time changes should be handled transparently, as the ubiquity of suspendable machines would require, but I'm well accustomed to seeing that mishandled. If you need to make a substantial change backwards to the time setting on your computer, just reboot it, as it's a safe bet that none of your software was tested against that use case. Sorry, but the above is not an acceptable solution. I know of more than one (embedded) device that needs an accurate clock but for which rebooting just to avoid a backward clock jump is unacceptable. Bart. Less clicking: Hotmail access on the new MSN homepage. _ Windows Live helps you keep up with all your friends, in one place. http://go.microsoft.com/?linkid=9660826-- Come build with us! The BlackBerryreg; Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9#45;12, 2009. Register now#33; http://p.sf.net/sfu/devconf___ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
Re: agent_check_and_process: select info
On Tue, Sep 15, 2009 at 11:16 PM, Mike Ayers mike_ay...@tvworks.com wrote: Then reboot! Apps (any apps) should certainly be able to handle clock changes, forward or back, of a second or less, without blinking. Time zone changes are nice to have, but some things barf on those (I have a cell phone that can't grasp the concept of moving between time zones). Forward time changes should be handled transparently, as the ubiquity of suspendable machines would require, but I'm well accustomed to seeing that mishandled. If you need to make a substantial change backwards to the time setting on your computer, just reboot it, as it's a safe bet that none of your software was tested against that use case. Sorry, but the above is not an acceptable solution. I know of more than one (embedded) device that needs an accurate clock but for which rebooting just to avoid a backward clock jump is unacceptable. Bart. -- Come build with us! The BlackBerryreg; Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9#45;12, 2009. Register now#33; http://p.sf.net/sfu/devconf ___ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
RE: agent_check_and_process: select info
I agree. On an embedded system, there are applications that can't be simply rebooted. There has to be a way for net-snmp agent to recover from this. Date: Wed, 16 Sep 2009 08:32:48 +0200 Subject: Re: agent_check_and_process: select info From: bart.vanass...@gmail.com To: mike_ay...@tvworks.com CC: sbazd...@hotmail.com; net-snmp-users@lists.sourceforge.net On Tue, Sep 15, 2009 at 11:16 PM, Mike Ayers mike_ay...@tvworks.com wrote: Then reboot! Apps (any apps) should certainly be able to handle clock changes, forward or back, of a second or less, without blinking. Time zone changes are nice to have, but some things barf on those (I have a cell phone that can't grasp the concept of moving between time zones). Forward time changes should be handled transparently, as the ubiquity of suspendable machines would require, but I'm well accustomed to seeing that mishandled. If you need to make a substantial change backwards to the time setting on your computer, just reboot it, as it's a safe bet that none of your software was tested against that use case. Sorry, but the above is not an acceptable solution. I know of more than one (embedded) device that needs an accurate clock but for which rebooting just to avoid a backward clock jump is unacceptable. Bart. _ New: Messenger sign-in on the MSN homepage http://go.microsoft.com/?linkid=9677403-- Come build with us! The BlackBerryreg; Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9#45;12, 2009. Register now#33; http://p.sf.net/sfu/devconf___ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
Re: agent_check_and_process: select info
On Tue, Sep 15, 2009 at 1:07 AM, Mike Ayers mike_ay...@tvworks.com wrote: From: Sam V [mailto:sbazd...@hotmail.com] Sent: Monday, September 14, 2009 7:04 AM Thanks, let me know if you have an idea for a fix? It is easy to reproduce. Just let snmp agent run then set the system date and time backwards. What is the operational requirement for setting the clock backwards? A remote-managed time machine? Please make yourself familiar with the operation of the ntpd process. ntpd can set the clock backwards, and this is a well documented aspect of the ntpd process. Bart. -- Come build with us! The BlackBerryreg; Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9#45;12, 2009. Register now#33; http://p.sf.net/sfu/devconf ___ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
RE: agent_check_and_process: select info
Yes, ntpd is running on my system and it can set time backwards. Date: Tue, 15 Sep 2009 08:22:13 +0200 Subject: Re: agent_check_and_process: select info From: bart.vanass...@gmail.com To: mike_ay...@tvworks.com CC: sbazd...@hotmail.com; net-snmp-users@lists.sourceforge.net On Tue, Sep 15, 2009 at 1:07 AM, Mike Ayers mike_ay...@tvworks.com wrote: From: Sam V [mailto:sbazd...@hotmail.com] Sent: Monday, September 14, 2009 7:04 AM Thanks, let me know if you have an idea for a fix? It is easy to reproduce. Just let snmp agent run then set the system date and time backwards. What is the operational requirement for setting the clock backwards? A remote-managed time machine? Please make yourself familiar with the operation of the ntpd process. ntpd can set the clock backwards, and this is a well documented aspect of the ntpd process. Bart. _ New! Faster Messenger access on the new MSN homepage http://go.microsoft.com/?linkid=9677406-- Come build with us! The BlackBerryreg; Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9#45;12, 2009. Register now#33; http://p.sf.net/sfu/devconf___ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
RE: agent_check_and_process: select info
From: Bart Van Assche [mailto:bart.vanass...@gmail.com] Sent: Monday, September 14, 2009 11:22 PM Thanks, let me know if you have an idea for a fix? It is easy to reproduce. Just let snmp agent run then set the system date and time backwards. What is the operational requirement for setting the clock backwards? A remote-managed time machine? Please make yourself familiar with the operation of the ntpd process. ntpd can set the clock backwards, and this is a well documented aspect of the ntpd process. Perhaps I misunderstand. NTPD, in normal operation, changes the clocks by tiny amounts. As I read the problem, adjusting the clock backwards by ten microseconds would cause the snmp_select_info() call to not return until at least ten more microseconds had lapsed. This should hardly cause any real problem. Is the issue more severe than this? Mike -- Come build with us! The BlackBerryreg; Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9#45;12, 2009. Register now#33; http://p.sf.net/sfu/devconf ___ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
RE: agent_check_and_process: select info
Well, if ntpd starts up and time really of then there can be a big change, Subject: RE: agent_check_and_process: select info Date: Tue, 15 Sep 2009 10:48:53 -0700 From: mike_ay...@tvworks.com To: bart.vanass...@gmail.com CC: sbazd...@hotmail.com; net-snmp-users@lists.sourceforge.net From: Bart Van Assche [mailto:bart.vanass...@gmail.com] Sent: Monday, September 14, 2009 11:22 PM Thanks, let me know if you have an idea for a fix? It is easy to reproduce. Just let snmp agent run then set the system date and time backwards. What is the operational requirement for setting the clock backwards? A remote-managed time machine? Please make yourself familiar with the operation of the ntpd process. ntpd can set the clock backwards, and this is a well documented aspect of the ntpd process. Perhaps I misunderstand. NTPD, in normal operation, changes the clocks by tiny amounts. As I read the problem, adjusting the clock backwards by ten microseconds would cause the snmp_select_info() call to not return until at least ten more microseconds had lapsed. This should hardly cause any real problem. Is the issue more severe than this? Mike _ New! Faster Messenger access on the new MSN homepage http://go.microsoft.com/?linkid=9677406-- Come build with us! The BlackBerryreg; Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9#45;12, 2009. Register now#33; http://p.sf.net/sfu/devconf___ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
Re: agent_check_and_process: select info
On Tue, Sep 15, 2009 at 7:48 PM, Mike Ayers mike_ay...@tvworks.com wrote: From: Bart Van Assche [mailto:bart.vanass...@gmail.com] Sent: Monday, September 14, 2009 11:22 PM Thanks, let me know if you have an idea for a fix? It is easy to reproduce. Just let snmp agent run then set the system date and time backwards. What is the operational requirement for setting the clock backwards? A remote-managed time machine? Please make yourself familiar with the operation of the ntpd process. ntpd can set the clock backwards, and this is a well documented aspect of the ntpd process. Perhaps I misunderstand. NTPD, in normal operation, changes the clocks by tiny amounts. As I read the problem, adjusting the clock backwards by ten microseconds would cause the snmp_select_info() call to not return until at least ten more microseconds had lapsed. This should hardly cause any real problem. Is the issue more severe than this? Small differences between the reference clock and the local clock will be applied gradually, large differences will be applied at once. This is configurable via the tinker step parameter in ntp.conf, which defaults to 0.128s. See also http://www.cis.udel.edu/~mills/ntp/html/miscopt.html. Bart. -- Come build with us! The BlackBerryreg; Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9#45;12, 2009. Register now#33; http://p.sf.net/sfu/devconf ___ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
RE: agent_check_and_process: select info
Then reboot! Apps (any apps) should certainly be able to handle clock changes, forward or back, of a second or less, without blinking. Time zone changes are nice to have, but some things barf on those (I have a cell phone that can't grasp the concept of moving between time zones). Forward time changes should be handled transparently, as the ubiquity of suspendable machines would require, but I'm well accustomed to seeing that mishandled. If you need to make a substantial change backwards to the time setting on your computer, just reboot it, as it's a safe bet that none of your software was tested against that use case. HTH, Mike -Original Message- From: Sam V [mailto:sbazd...@hotmail.com] Sent: Tuesday, September 15, 2009 11:36 AM To: net-snmp users Subject: RE: agent_check_and_process: select info Well, if ntpd starts up and time really of then there can be a big change, Subject: RE: agent_check_and_process: select info Date: Tue, 15 Sep 2009 10:48:53 -0700 From: mike_ay...@tvworks.com To: bart.vanass...@gmail.com CC: sbazd...@hotmail.com; net-snmp-users@lists.sourceforge.net From: Bart Van Assche [mailto:bart.vanass...@gmail.com] Sent: Monday, September 14, 2009 11:22 PM Thanks, let me know if you have an idea for a fix? It is easy to reproduce. Just let snmp agent run then set the system date and time backwards. What is the operational requirement for setting the clock backwards? A remote-managed time machine? Please make yourself familiar with the operation of the ntpd process. ntpd can set the clock backwards, and this is a well documented aspect of the ntpd process. Perhaps I misunderstand. NTPD, in normal operation, changes the clocks by tiny amounts. As I read the problem, adjusting the clock backwards by ten microseconds would cause the snmp_select_info() call to not return until at least ten more microseconds had lapsed. This should hardly cause any real problem. Is the issue more severe than this? Mike New! Hotmail sign-in on the MSN homepage. http://go.microsoft.com/?linkid=9677401 -- Come build with us! The BlackBerryreg; Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9#45;12, 2009. Register now#33; http://p.sf.net/sfu/devconf ___ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
RE: agent_check_and_process: select info
Thanks, let me know if you have an idea for a fix? It is easy to reproduce. Just let snmp agent run then set the system date and time backwards. Subject: Re: agent_check_and_process: select info From: ma...@lysator.liu.se To: sbazd...@hotmail.com CC: net-snmp-cod...@lists.sourceforge.net Date: Fri, 11 Sep 2009 08:11:31 +0200 On Wed, 2009-09-09 at 10:39 -0400, Samer Vazdekis wrote: Hi there, I'm running net-snmp version 5.2.1.2. I'm coming across a problem in snmp_select_info(). This part of code didn't change when I compared it to version 5.4.2. Basically, this is using gettimeofday() to figure out the timeouts. When I reset system date and time, specially backwards, the select fails and keeps on failing until I set back the date and time. I'm considering a solution that changes the request's time, expire, and timeout values (in netsnmp_request_list) if current time is found to be less than the time the request was created. Pleae, let me know your opinion. Or maybe if there is already a fix for this. This is a hard problem. The problem is that there are two concepts - wait for X time units and wait until time T - but only one interface to handle it. Check out the thread Patch for delaying of tasks attached to snmp_alarm_register from september-october 2005 for a lot more description. http://thread.gmane.org/gmane.network.net-snmp.devel/10570/focus=10634 There is also an earlier stab on the problem in https://sourceforge.net/tracker/?func=detailatid=312694aid=2505488group_id=12694 /MF I think I will have to do a FAQ of this... _ Click less, chat more: Messenger on MSN.ca http://go.microsoft.com/?linkid=9677404-- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july___ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
RE: agent_check_and_process: select info
From: Sam V [mailto:sbazd...@hotmail.com] Sent: Monday, September 14, 2009 7:04 AM Thanks, let me know if you have an idea for a fix? It is easy to reproduce. Just let snmp agent run then set the system date and time backwards. What is the operational requirement for setting the clock backwards? A remote-managed time machine? Thanks, Mike -- Come build with us! The BlackBerryreg; Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9#45;12, 2009. Register now#33; http://p.sf.net/sfu/devconf ___ Net-snmp-users mailing list Net-snmp-users@lists.sourceforge.net Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users
