[Wien] lapw1 vs lapwso speed

[pluto]

Dear All,

When calculating bands for a large slab I have following sequence:

Sun May 14 12:33:03 PM CEST 2023> (x) lapw1 -band -up -p
Sun May 14 02:25:26 PM CEST 2023> (x) lapw1 -band -dn -p
Sun May 14 04:17:22 PM CEST 2023> (x) lapwso -up -p
Mon May 15 01:30:05 AM CEST 2023> (x) qtl -up -p -band -so
Mon May 15 01:30:05 AM CEST 2023> (x) lapw2 -p -fermi -so -up
Mon May 15 01:51:51 AM CEST 2023> (x) qtl -dn -p -band -so
Mon May 15 01:51:51 AM CEST 2023> (x) lapw2 -p -fermi -so -dn

As you can see lapwso takes much longer than lapw1 (approx. 9h vs 2h). 
Is this normal for band calculations?

I have 128 GB of RAM in this computer, so this is not a RAM issue. Here 
is what top shows for the lapwso calculation (I have 4 parallel 
localhost processes in .machines, OMP=2 and no mpi):

Tasks: 505 total,   2 running, 503 sleeping,   0 stopped,   0 zombie
%Cpu(s): 24.0 us,  0.2 sy,  0.0 ni, 75.7 id,  0.0 wa,  0.1 hi,  0.0 si,  
0.0 st
MiB Mem : 128047.1 total,   1845.8 free,  16809.0 used, 111158.6 
buff/cache
MiB Swap:  32088.0 total,  31471.5 free,    616.5 used. 111238.1 avail 
Mem

     PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ 
COMMAND
1336417 lplucin   20   0 6417856   4.8g  15840 R 199.3   3.8   1294:13 
lapwso
1336392 lplucin   20   0 2848204   2.3g  15880 S 146.8   1.9   1295:30 
lapwso
1336391 lplucin   20   0 2848188   2.4g  15916 S 130.6   1.9   1304:23 
lapwso
1336396 lplucin   20   0 2848060   2.3g  15816 S  99.7   1.9   1288:06 
lapwso

.machines file:

omp_global:8
omp_lapw1:2
omp_lapw2:2
omp_lapwso:2
1:localhost
1:localhost
1:localhost
1:localhost
granularity:1

Best,
Lukasz