beagleboard-x15 openssl rsa vs nistp256

Architecture:        armv7l
Byte Order:          Little Endian
CPU(s):              2
On-line CPU(s) list: 0,1
Thread(s) per core:  1
Core(s) per socket:  2
Socket(s):           1
Vendor ID:           ARM
Model:               2
Model name:          Cortex-A15
Stepping:            r2p2
CPU max MHz:         1500.0000
CPU min MHz:         1000.0000
BogoMIPS:            18.44
Flags:               half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm
              total        used        free      shared  buff/cache   available
Mem:           1625          43        1332          12         248        1516
Swap:             0           0           0
### openssl speed
Doing 2048 bits private rsa's for 10s: 1340 2048 bits private RSA's in 10.00s
Doing 2048 bits public rsa's for 10s: 60679 2048 bits public RSA's in 10.00s
Doing 3072 bits private rsa's for 10s: 494 3072 bits private RSA's in 10.00s
Doing 3072 bits public rsa's for 10s: 30039 3072 bits public RSA's in 10.00s
Doing 4096 bits private rsa's for 10s: 235 4096 bits private RSA's in 10.02s
Doing 4096 bits public rsa's for 10s: 17744 4096 bits public RSA's in 10.00s
Doing 256 bits sign ecdsa's for 10s: 38302 256 bits ECDSA signs in 9.99s
Doing 256 bits verify ecdsa's for 10s: 14429 256 bits ECDSA verify in 10.00s
OpenSSL 1.1.1d  10 Sep 2019
built on: Mon Dec  7 20:44:45 2020 UTC
options:bn(64,32) rc4(char) des(long) aes(partial) blowfish(ptr)
compiler: gcc -fPIC -pthread -Wa,--noexecstack -Wall -Wa,--noexecstack -g -O2 -fdebug-prefix-map=/build/openssl-vAuCFH/openssl-1.1.1d=. -fstack-protector-strong -Wformat -Werror=format-security -DOPENSSL_USE_NODELETE -DOPENSSL_PIC -DOPENSSL_CPUID_OBJ -DOPENSSL_BN_ASM_MONT -DOPENSSL_BN_ASM_GF2m -DSHA1_ASM -DSHA256_ASM -DSHA512_ASM -DKECCAK1600_ASM -DAES_ASM -DBSAES_ASM -DGHASH_ASM -DECP_NISTZ256_ASM -DPOLY1305_ASM -DNDEBUG -Wdate-time -D_FORTIFY_SOURCE=2
                  sign    verify    sign/s verify/s
rsa 2048 bits 0.007463s 0.000165s    134.0   6067.9
rsa 3072 bits 0.020243s 0.000333s     49.4   3003.9
rsa 4096 bits 0.042638s 0.000564s     23.5   1774.4
                              sign    verify    sign/s verify/s
 256 bits ecdsa (nistp256)   0.0003s   0.0007s   3834.0   1442.9