Hi, I want to enforce migration of thread+allocated memory to another lgroup but failed for some threads.
I understand from the "Memory and Thread Placement Optimization Developer's Guide", that there is no hard memory affinity in Solaris, but only the possibility to define some level of affinity to the home lgroup. Therefore, prior to any kind of memory migration it seems necessary to move the home lgroup to the lgroup where the memory should migrate to. The lgrp_home(3LGRP) man page defines the "home lgroup" of a thread as the "lgroup with the strongest affinity that the thread can run on". A sequence for memory migration was already lined out in http://www.opensolaris.org/jive/thread.jspa?messageID=14792: - Change the thread in questions home lgroup to the CPU where you want the memory allocated, - use 'pmadvise -o heap=lwp_access' on the process - the memory should now get allocated in the newly homed lgrp (check with 'pmap -L' and lgrpinfo (if the allocation is large enough to notice)). - rehome the lgrp to another CPU or just bind it. I tried, but for some threads, I got surprising results: > ./plgrp -a all 27215 PID/LWPID HOME AFFINITY 27215/1 2 5/strong,0-4,6-24/none If the home lgroup is defined as the lgroup with the strongest affinity, isn't the output above somewhat contradictory? > ./plgrp -F -H 5 27215 PID/LWPID HOME 27215/1 2 => 2 This thread seems to be resistant to plgrp's attempts to assign a new home lgroup (option -H) to it. This is a test program. For some other threads, I was able to freely rehome them to any lgroup in the range 1..8 (the leaf lgroups). Has anyone some further suggestions on what could prevent reassigning the home lgroup? My system is a Sun Fire X4600 with eight dual-core Opterons. Lgroups 1..8 are identical (i.e. same amount of memory and CPU resources per lgroup), except for the CPU IDs: > lgrpinfo.pl -a [..] lgroup 1 (leaf): Children: none, Parent: 9 CPUs: 0 1 Memory: installed 3584 Mb, allocated 985 Mb, free 2599 Mb Lgroup resources: 1 (CPU); 1 (memory) Load: 0.00723 Latency: 51 [..] > psrinfo 0 on-line since 11/12/2008 13:38:11 1 on-line since 11/12/2008 13:38:15 2 on-line since 11/12/2008 13:38:17 3 on-line since 11/12/2008 13:38:19 4 on-line since 11/12/2008 13:38:21 5 on-line since 11/12/2008 13:38:23 6 on-line since 11/12/2008 13:38:25 7 on-line since 11/12/2008 13:38:27 8 on-line since 11/12/2008 13:38:29 9 on-line since 11/12/2008 13:38:31 10 on-line since 11/12/2008 13:38:33 11 on-line since 11/12/2008 13:38:35 12 on-line since 11/12/2008 13:38:37 13 on-line since 11/12/2008 13:38:39 14 on-line since 11/12/2008 13:38:41 15 on-line since 11/12/2008 13:38:43 Thanks, Manfred -- This message posted from opensolaris.org _______________________________________________ perf-discuss mailing list perf-discuss@opensolaris.org
