Merge release-5-0 into master

[alexxy/gromacs.git] / src / programs / mdrun / md.cpp

diff --git a/src/programs/mdrun/md.cpp b/src/programs/mdrun/md.cpp
index 9864f8789f9385d2e536ed33f5988bacff85186e..0504150c008e23e09337d2774f24662f049a6474 100644 (file)
--- a/src/programs/mdrun/md.cpp
+++ b/src/programs/mdrun/md.cpp
@@ -1881,6 +1881,21 @@ double do_md(FILE *fplog, t_commrec *cr, int nfile, const t_filenm fnm[],
                     }
                     dd_bcast(cr->dd, sizeof(gmx_bool), &bPMETuneRunning);
 
+                    if (bPMETuneRunning &&
+                        use_GPU(fr->nbv) && DOMAINDECOMP(cr) &&
+                        !(cr->duty & DUTY_PME))
+                    {
+                        /* Lock DLB=auto to off (does nothing when DLB=yes/no).
+                         * With GPUs + separate PME ranks, we don't want DLB.
+                         * This could happen when we scan coarse grids and
+                         * it would then never be turned off again.
+                         * This would hurt performance at the final, optimal
+                         * grid spacing, where DLB almost never helps.
+                         * Also, DLB can limit the cut-off for PME tuning.
+                         */
+                        dd_dlb_set_lock(cr->dd, TRUE);
+                    }
+
                     if (bPMETuneRunning || step_rel > ir->nstlist*50)
                     {
                         bPMETuneTry     = FALSE;
@@ -1911,6 +1926,16 @@ double do_md(FILE *fplog, t_commrec *cr, int nfile, const t_filenm fnm[],
                     {
                         calc_enervirdiff(NULL, ir->eDispCorr, fr);
                     }
+
+                    if (!bPMETuneRunning &&
+                        DOMAINDECOMP(cr) &&
+                        dd_dlb_is_locked(cr->dd))
+                    {
+                        /* Unlock the DLB=auto, DLB is allowed to activate
+                         * (but we don't expect it to activate in most cases).
+                         */
+                        dd_dlb_set_lock(cr->dd, FALSE);
+                    }
                 }
                 cycles_pmes = 0;
             }