<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black; background-color: rgb(255, 255, 255)">
<span style="margin: 0px">I'm running into an issue where processes sometimes hang when calling MPI_Finalize. This happens with both versions 3.3.2 and 3.4a2 on a single node RedHat 7.5 x86-64 machine, when MPICH is compiled with PGI 20.1 with these configuration
flags</span><br>
</div>
<div style="margin: 0px; font-size: 15px; font-family: "Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif; color: rgb(32, 31, 30); background-color: rgb(255, 255, 255)">
<div dir="ltr" style="margin: 0px">
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
<br>
--enable-debug --enable-shared --enable-debuginfo --enable-sharedlib=gcc</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
<br>
</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
If I change the default optimization level (-O2) by configuring with</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
<br>
</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
--enable-fast=O1<br>
</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
<br>
</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
as well, the hang doesn't occur. Another data point is that the hang does not occur with PGI 19.5 with either optimization levels.</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
<br>
</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
I have been testing with the cpi.c code in the examples folder built with just</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
<br>
</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
mpicc cpi.c</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
mpiexec -n 3 ./a.out<br>
</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
<br>
</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
Here is a the backtrace from one of the processes that is hanging</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
<br>
</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
<span style="margin: 0px">(gdb) bt<br>
</span>
<div style="margin: 0px">#0 MPID_nem_mpich_blocking_recv ()<br>
</div>
<div style="margin: 0px"> at /tmp/mpich-3.3.2/build/../src/mpid/ch3/channels/nemesis/include/mpid_nem_inline.h:1038<br>
</div>
<div style="margin: 0px">#1 MPIDI_CH3I_Progress () at ../src/mpid/ch3/channels/nemesis/src/ch3_progress.c:506<br>
</div>
<div style="margin: 0px">#2 0x00000000004fc88d in MPIDI_CH3U_VC_WaitForClose ()<br>
</div>
<div style="margin: 0px"> at ../src/mpid/ch3/src/ch3u_handle_connection.c:383<br>
</div>
<div style="margin: 0px">#3 0x0000000000442364 in MPID_Finalize () at ../src/mpid/ch3/src/mpid_finalize.c:110<br>
</div>
<div style="margin: 0px">#4 0x0000000000408621 in PMPI_Finalize () at ../src/mpi/init/finalize.c:260<br>
</div>
<div style="margin: 0px">#5 0x00000000004023e5 in main () at cpi.c:59<br>
</div>
<span style="margin: 0px"></span><br>
</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
Is there a potential fix to be made to MPICH to prevent processes hanging when MPICH is compiled with the default optimization level?</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
<br>
</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
Thanks,</div>
<div style="margin: 0px; font-size: 12pt; font-family: Calibri, Arial, Helvetica, sans-serif; color: black">
Kent</div>
</div>
</div>
</div>
IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose,
or store or copy the information in any medium. Thank you.
</body>
</html>