Read-ahead was off, so OpenSSL read every record in two calls, its
header and then its body. It was off because ssl_poll() asks
ssl_pending(), and SSL_pending() does not count data read ahead and not
yet decrypted: poll() would wait while data waits in OpenSSL.
SSL_has_pending() does count it. With OpenSSL 1.1.0 and later, which
have it, ssl_pending() uses it and records are read ahead; with older
ones and wolfSSL nothing changes.
SSL_has_pending() is also true when only a part of a record has been
read ahead, which is no data yet: poll() would then return at once, over
and over and without its timeout, until the rest came. ssl_pending()
says so only when decrypted data waits, or when what was read ahead
makes a whole record (SSL_peek() of one byte, the sockets not blocking);
otherwise the socket is polled for the rest.
Decrypting TLS streams takes 9-14% less time for the same data (ARM).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
