g10/decrypt-data: use iobuf_read for higher performance

* g10/decrypt-data.c (fill_buffer): Use iobuf_read instead of iobuf_get
for reading data.
--

This patch reduces iobuf_read per byte processing overhead and speeds
up decryption.

Benchmark results below, tested on Intel Core i7-4790K (turbo off).
Encrypted 2 GiB through pipe to ramfs file using AES128. Decrypt
ramfs file out through pipe to /dev/null.

before patch-set
----------------
	       gpg process
no-armor:      user time    pipe transfer rate
 encrypt-aead:  1.02         1.0 GB/s
 decrypt-aead:  10.8         185 MB/s
 encrypt-cfb:   4.8          342 MB/s
 decrypt-cfb:   12.7         157 MB/s

               gpg process
armor:         user time    pipe transfer rate
 encrypt-aead:  13.8         140 MB/s
 decrypt-aead:  30.6         68 MB/s
 encrypt-cfb:   17.4         114 MB/s
 decrypt-cfb:   32.6         64 MB/s

after (decrypt opt)
-------------------
               gpg process
no-armor:      user time    pipe transfer rate
 decrypt-aead:  7.3          263 MB/s
 decrypt-cfb:   9.3          211 MB/s

               gpg process
armor:         user time    pipe transfer rate
 decrypt-aead:  27.0         77 MB/s
 decrypt-cfb:   29.0         72 MB/s

Note: decryption results are much slower than encryption because of
extra SHA1 & RIPEMD160 hashing.

GnuPG-bug-id: 3786
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
This commit is contained in:
Jussi Kivilinna 2018-11-08 21:31:12 +02:00
parent e2b9095de3
commit 5d6c080522
1 changed files with 19 additions and 8 deletions

View File

@ -551,31 +551,42 @@ fill_buffer (decode_filter_ctx_t dfx, iobuf_t stream,
byte *buffer, size_t nbytes, size_t offset)
{
size_t nread = offset;
int c;
size_t curr;
int ret;
if (dfx->partial)
{
for (; nread < nbytes; nread++ )
while (nread < nbytes)
{
if ((c = iobuf_get (stream)) == -1)
curr = nbytes - nread;
ret = iobuf_read (stream, &buffer[nread], curr);
if (ret == -1)
{
dfx->eof_seen = 1; /* Normal EOF. */
break;
}
buffer[nread] = c;
nread += ret;
}
}
else
{
for (; nread < nbytes && dfx->length; nread++, dfx->length--)
while (nread < nbytes && dfx->length)
{
c = iobuf_get (stream);
if (c == -1)
curr = nbytes - nread;
if (curr > dfx->length)
curr = dfx->length;
ret = iobuf_read (stream, &buffer[nread], curr);
if (ret == -1)
{
dfx->eof_seen = 3; /* Premature EOF. */
break;
}
buffer[nread] = c;
nread += ret;
dfx->length -= ret;
}
if (!dfx->length)
dfx->eof_seen = 1; /* Normal EOF. */