<div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Sep 18, 2020 at 10:23 AM Barry Smith <<a href="mailto:bsmith@petsc.dev">bsmith@petsc.dev</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div style="overflow-wrap: break-word;"><br><div> This email thread doesn't seem to have clear communication. Can we start at the beginning again please? Please answer my questions directly in the appropriate lines below in your email response so we know what answer goes with what question. I know you have done some of these things but it is unclear what order you did them and the order is important.</div><div><br></div><div> Background: In order to decide if the test in MPI.py works, or needs to be modified or removed we need clear information about your system BEFORE you made changes to get things to work. </div><div><br></div><div> 1) Did you add the </div><div><br></div><div> 127.0.0.1 MarksMac-5.local</div><div><br></div><div> to the /etc/hosts yesterday because Satish suggested it, or have you had it there for a long time? (You should not need it)</div></div></blockquote><div><br></div><div>Satish suggested MarksMac-302.local.</div><div><br></div><div>As I said earlier I have seen messages that say something like a network problem, renaming hostname to MarksMac-X.local, where X is +1 the current X. Initially it was MarksMac.local and it made MarksMac-1.local</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div style="overflow-wrap: break-word;"><div><br></div><div> 2) Please run </div><div><br></div><div> ping -c 2 `hostname`</div></div></blockquote><div><br></div>09:08 master *= ~/Codes/petsc$ ping -c 2 `hostname`<br>PING marksmac-302.local (127.0.0.1): 56 data bytes<br>Request timeout for icmp_seq 0<br><br>--- marksmac-302.local ping statistics ---<br>2 packets transmitted, 0 packets received, 100.0% packet loss<br><div>10:55 2 master *= ~/Codes/petsc$</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div style="overflow-wrap: break-word;"><div><br></div><div> 3) Please remove the line 127.0.0.1 MarksMac-5.local in /etc/hosts and follow the directions in</div><div><br></div><div> <a href="https://stackoverflow.com/questions/37951379/etc-hosts-ignored-in-mac-el-capitan-10-11-5" target="_blank">https://stackoverflow.com/questions/37951379/etc-hosts-ignored-in-mac-el-capitan-10-11-5</a></div><div><br></div><div> to flush the DNS cache (note for different versions of MacOS the command is different).</div></div></blockquote><div><br></div><div>My takeway here was you need one space between the IP and name. I had a tab here:</div><div><br></div><div>127.0.0.1 localhost<br></div><div><br></div><div>fixed, but did not help. Its not clear to me what you want me to do. He did two scary (sudo goop) things. One was:</div><div><br></div><div><span style="color:rgb(83,90,96);font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;font-size:15px">sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist</span><br></div><div><span style="color:rgb(83,90,96);font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;font-size:15px"><br></span></div><div><span style="color:rgb(83,90,96);font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;font-size:15px">Do you want me to do that?</span></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div style="overflow-wrap: break-word;"><div><br></div><div> 4) Please run </div><div><br></div><div> ping -c 2 `hostname`</div><div><br></div><div> 5) Please run a MPI program (doesn't matter which and I don't care how you installed MPICH or OpenMPI) with</div><div><br></div><div> mpiexec -n 2 ./programname </div><div><br></div><div> does it run, hang or ?</div><div><br></div><div><br></div><div> Based on this information we can decide what needs to be done next.</div><div><br></div><div> Thanks</div><div><br></div><div> Barry</div><div><br></div><div>As a side note on my Mac</div><div><br></div><div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">$ hostname</span></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">Barrys-MacBook-Pro-3.local</span></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo;color:rgb(200,20,201)"><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">~/Src/petsc</span><span style="font-variant-ligatures:no-common-ligatures"><b> (barry/2020-07-07/docs-no-makefiles *>)</b></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)"> arch-docs-no-makefiles</span></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">$ /sbin/ping -c 2 `hostname`</span></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">PING barrys-macbook-pro-3.local (127.0.0.1): 56 data bytes</span></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">64 bytes from <a href="http://127.0.0.1" target="_blank">127.0.0.1</a>: icmp_seq=0 ttl=64 time=0.077 ms</span></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">64 bytes from <a href="http://127.0.0.1" target="_blank">127.0.0.1</a>: icmp_seq=1 ttl=64 time=0.112 ms</span></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo;min-height:16px"><span style="font-variant-ligatures:no-common-ligatures"></span><br></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">--- barrys-macbook-pro-3.local ping statistics ---</span></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">2 packets transmitted, 2 packets received, 0.0% packet loss</span></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">round-trip min/avg/max/stddev = 0.077/0.095/0.112/0.018 ms</span></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo;color:rgb(200,20,201)"><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">~/Src/petsc</span><span style="font-variant-ligatures:no-common-ligatures"><b> (barry/2020-07-07/docs-no-makefiles *>)</b></span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)"> arch-docs-no-makefiles</span></div><div style="margin:0px;font-stretch:normal;font-size:14px;line-height:normal;font-family:Menlo"><span style="font-variant-ligatures:no-common-ligatures">$ </span></div><div><br></div><div><span style="font-variant-ligatures:no-common-ligatures">We are trying to understand if/why your machine is behaving differently.</span></div><div><span style="font-variant-ligatures:no-common-ligatures"><br></span></div><div><span style="font-variant-ligatures:no-common-ligatures">My theory is that if ping -c 2 `hostname` fails then MPICH and OpenMP mpiexec -n 2 will fail. We need to determine if this theory is correct or if you have a counter-example.</span></div><div><span style="font-variant-ligatures:no-common-ligatures"><br></span></div></div><div><br></div><div><blockquote type="cite"><div>On Sep 18, 2020, at 8:09 AM, Mark Adams <<a href="mailto:mfadams@lbl.gov" target="_blank">mfadams@lbl.gov</a>> wrote:</div><br><div><div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Sep 18, 2020 at 7:51 AM Matthew Knepley <<a href="mailto:knepley@gmail.com" target="_blank">knepley@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr">On Fri, Sep 18, 2020 at 7:46 AM Mark Adams <<a href="mailto:mfadams@lbl.gov" target="_blank">mfadams@lbl.gov</a>> wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Oh you did not change my hostname:<div><br></div><div>07:37 master *= ~/Codes/petsc$ hostname<br>MarksMac-302.local<br>07:41 master *= ~/Codes/petsc$ ping -c 2 MarksMac-302.local<br>PING marksmac-302.local (127.0.0.1): 56 data bytes<br>Request timeout for icmp_seq 0<br><br>--- marksmac-302.local ping statistics ---<br>2 packets transmitted, 0 packets received, 100.0% packet loss<br>07:42 2 master *= ~/Codes/petsc$</div></div></blockquote><div><br></div><div>This does not make sense to me. You have</div><div><br></div><div> 127.0.0.1 MarksMac-302.local</div><div><br></div><div>in /etc/hosts, </div></div></div></blockquote><div><br></div><div>09:07 ~/.ssh$ cat /etc/hosts<br>##<br># Host Database<br>#<br># localhost is used to configure the loopback interface<br># when the system is booting. Do not change this entry.<br>##<br>127.0.0.1 localhost<br>255.255.255.255 broadcasthost<br>127.0.0.1 MarksMac-5.local<br>127.0.0.1 <a href="http://243.124.240.10.in-addr.arpa.private.cam.ac.uk/" target="_blank">243.124.240.10.in-addr.arpa.private.cam.ac.uk</a><br>127.0.0.1 MarksMac-302.local<br>09:07 ~/.ssh$<br><br></div><div><br></div><div><br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div class="gmail_quote"><div>but you cannot resolve that name?</div><div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>BTW, I used to get messages about some network issue and 'changing host name to MarksMac-[x+1].local'. That is, the original hostname was MarksMac.local, then I got a message about changing to MarksMac-1.local, etc. I have not seen these messages for months but apparently this process has continued unabated.</div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Sep 17, 2020 at 11:10 PM Satish Balay via petsc-users <<a href="mailto:petsc-users@mcs.anl.gov" target="_blank">petsc-users@mcs.anl.gov</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Thu, 17 Sep 2020, Matthew Knepley wrote:<br>
<br>
> On Thu, Sep 17, 2020 at 8:33 PM Barry Smith <<a href="mailto:bsmith@petsc.dev" target="_blank">bsmith@petsc.dev</a>> wrote:<br>
> <br>
> > > On Sep 17, 2020, at 4:59 PM, Satish Balay via petsc-users <<br>
> > <a href="mailto:petsc-users@mcs.anl.gov" target="_blank">petsc-users@mcs.anl.gov</a>> wrote:<br>
> > ><br>
> > > Here is a fix:<br>
> > ><br>
> > > echo 127.0.0.1 `hostname` | sudo tee -a /etc/hosts<br>
> ><br>
> > Satish,<br>
> ><br>
> > I don't think you want to be doing this on a Mac (on anything?) On a<br>
> > Mac based on the network configuration etc as it boots up and as networks<br>
> > are accessible or not (wi-fi) it determines what hostname should be, one<br>
> > should never being hardwiring it to some value.<br>
> ><br>
> <br>
> Satish is just naming the loopback interface. I did this on all my former<br>
> Macs.<br>
<br>
<br>
Yes - this doesn't change the hostname. Its just adding an entry for gethostbyname - for current hostname.<br>
<br>
>>><br>
127.0.0.1 MarksMac-302.local<br>
<<<<br>
<br>
Sure - its best to not do this when one has a proper IP name [like <a href="http://foo.mcs.anl.gov/" rel="noreferrer" target="_blank">foo.mcs.anl.gov</a>] - but its useful when one has a hostname like "MarksMac-302.local" -that is not DNS resolvable<br>
<br>
Even if the machine is moved to a different network with a different name - the current entry won't cause problems [but will need another entry for the new host name - if this new name is also not DNS resolvable]<br>
<br>
Its likely this file is a generated file on macos - so might get reset on reboot - or some network change? [if this is the case - the change won't be permanent]<br>
<br>
<br>
Satish<br>
</blockquote></div>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener</div><div><br></div><div><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank">https://www.cse.buffalo.edu/~knepley/</a><br></div></div></div></div></div></div></div></div>
</blockquote></div></div>
</div></blockquote></div><br></div></blockquote></div></div>