Chapril/xmpp.chapril.org-ejabberd
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Decrease CPU usage caused by tls:send with large data.

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Sending one large chunk of data with tls:send eats lots of
CPU power and blocks whole Erlang emulator. This is caused by the
fact that encrypted output is read from memory BIO in 1k chunks.
Memory BIO, after reading data, shifts the remaining part.
If large chunks of data (few MB) is sent and then read in 1k
chunks, then a _lot_ of shifting is performed eating CPU.

The solution is to simply allocate binary of the needed size
(amount of data in memory BIO can be retrieved with
BIO_ctrl_pending) and then issue only one read that reads the
whole data.
This commit is contained in:
Janusz Dziemidowicz 2011-09-20 21:20:51 +02:00 committed by Badlop
parent 32ff6b56eb
commit c4f9a050c9
1 changed files with 3 additions and 13 deletions
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16
src/tls/tls_drv.c
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@ -407,22 +407,12 @@ static int tls_drv_control(ErlDrvData handle,
break; break;
case GET_ENCRYPTED_OUTPUT: case GET_ENCRYPTED_OUTPUT:
die_unless(d->ssl, "SSL not initialized"); die_unless(d->ssl, "SSL not initialized");
size = BUF_SIZE + 1; size = BIO_ctrl_pending(d->bio_write) + 1;
rlen = 1;
b = driver_alloc_binary(size); b = driver_alloc_binary(size);
b->orig_bytes[0] = 0; b->orig_bytes[0] = 0;
while ((res = BIO_read(d->bio_write, BIO_read(d->bio_write, b->orig_bytes + 1, size - 1);
b->orig_bytes + rlen, BUF_SIZE)) > 0)
{
//printf("%d bytes of encrypted data read from state machine\r\n", res);
rlen += res;
size += BUF_SIZE;
b = driver_realloc_binary(b, size);
}
b = driver_realloc_binary(b, rlen);
*rbuf = (char *)b; *rbuf = (char *)b;
return rlen; return size;
case GET_DECRYPTED_INPUT: case GET_DECRYPTED_INPUT:
if (!SSL_is_init_finished(d->ssl)) if (!SSL_is_init_finished(d->ssl))
{ {