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__lll_lock_wait allowing only one thread to work
I am calling the XPRESS optimizer from a multithreaded Pascal application and having performance issues with the solver. While the program is multithreaded, all but one of the threads are sleeping a...
Your suggestion makes sense. CPU usage went up considerably, but still lower than expected and still displaying most threads waiting. Have a look at this:
(gdb) thread 45
[Switching to thread 45 (Thread 0x7fff693f4700 (LWP 2016384))]
#0 0x00007ffff7bc175d in __lll_lock_wait () from /lib64/libpthread.so.0
(gdb) frame 14
#14 0x00000000004c1959 in RESOLVER (this=0x7fff38562bb8) at ../../rchlib/mat/umipsimplex_xprs.pas:964
964 xprserrCode:=XPRSmipoptimize(pxprs,'d');
(gdb) print @pxprs
warning: can't find linker symbol for virtual table for `TMIPSIMPLEX_XPRS' value
$1 = (^XPRSPROB) 0x7fff38562cc0
(gdb) thread 46
[Switching to thread 46 (Thread 0x7fff68ff3700 (LWP 2016385))]
#0 0x00007ffff7bc175d in __lll_lock_wait () from /lib64/libpthread.so.0
(gdb) frame 14
#14 0x00000000004c1959 in RESOLVER (this=0x7fff2c649218) at ../../rchlib/mat/umipsimplex_xprs.pas:964
964 xprserrCode:=XPRSmipoptimize(pxprs,'d');
(gdb) print @pxprs
warning: can't find linker symbol for virtual table for `TMIPSIMPLEX_XPRS' value
$2 = (^XPRSPROB) 0x7fff2c649320The problems are being created once, i.e. no XPRScreateprob and XPRSdestroyprob everytime.