Ssl_write_client_key_exchange take too long time

Hi guys.I am porting mbedtls-2.16.1 by baremetal method. The processor is EFM32GG390 with Cortex-M3 core… The main frequency is 48MHz. Now I meet strange problem during handshaking process . It takes about 40 seconds for the step about ssl_write_client_key_exchange. I don’t know if it is caused by the slow speed of processor or there is some bug in my firmware, Who can give me some advice about it? Thank you!

Hi @ninesuntj
Asymmetric key operations consume much time, and very much dependent on the CPU.
If you are using ECC keys for your key exchange, have you considered using the non blocking ECC feature?
Mbed TLS Team member

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Thank for your support, I may try the ECC