https://jira.whamcloud.com This file is an XML representation of an issue en-us 9.4.14 940014 05-12-2023 https://jira.whamcloud.com/browse/LU-17353 Lustre <p>Occasionally seen in the logs that CPU cores are being deactivated on the system:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre>[ 200.214057] LNet: 5394:0:(libcfs_cpu.c:1133:cfs_cpu_dead()) Lustre: can't support CPU plug-out well now, performance and stability could be impacted [CPU 32] [ 200.231635] LNet: 5394:0:(libcfs_cpu.c:1133:cfs_cpu_dead()) Lustre: can't support CPU plug-out well now, performance and stability could be impacted [CPU 33] [ 200.249606] LNet: 5394:0:(libcfs_cpu.c:1133:cfs_cpu_dead()) Lustre: can't support CPU plug-out well now, performance and stability could be impacted [CPU 34]</pre> </div></div> <p>I suspect this is mainly a client issue, but could eventually be hit on servers in a cloud environment. </p> <p>It would be good to handle this situation better than just printing an error message. In particular, stop ptlrpcd threads running on those cores if the entire CPT is removed, so they don't continue to burn cycles. Also, recompute the CPT count. </p> LU-17353

cfs_cpu_dead() Lustre: can't support CPU plug-out well now

Bug Minor Open Unresolved WC Triage Andreas Dilger Sun, 10 Dec 2023 19:33:11 +0000 Sun, 10 Dec 2023 19:38:09 +0000 Lustre 2.14.0 0 1 <p>The important question is at which point the Lustre filesystem is mounted relative to when the cores are removed, and whether cores are removed that were initially available at mount time. There is no message printed when a new core is added, since that does not affect Lustre at all, and removing those cores that were previously added is not complex (the console error message could just be skipped for the case where there are no Lustre threads running there). However, removing cores that were previously in use by Lustre/LNet is much more difficult. Also, it would be much more complex if the cores are not added/removed in numerical order (i.e. core 31 is added, but core 0 is removed).</p> Related Development Rank 1|i044fz: Rank (Obsolete) 9223372036854775807 Severity