some questions about uct_iface_attr.cap.am

[w7658610]

uct_iface_attr.cap.am
max_short,max_bcopy,max_zcopy, has different sizes。
when I use rc_verbs/mlx5_0:1 :
short : max supported: 123
bcopy : max supported: 8255
zcopy : ax supported: 8255

when I use tcp/ib0:
short : max supported: 8192
bcopy : max supported: 8192
zcopy : max supported: 65536

Are these parameters unchangeable?
Do I have to shard data if I want to send larger data? thx.

[brminich]

These parameters can not be changed during iface lifetime, but you have to query them for every opened iface.
Yes, you'd need to send multiple fragments if you have to send data larger than these thresholds

[w7658610]

Isn't ZCopy optimized for large packages?
I am wondering whether 64K is too small？ For RDMA

[w7658610]

In uct_hello_world.c ,
when I use uct_iface_query,the max supported became very small。Why is that?