Mailing List Archive

* g10/armor.c (asctobin): Larger look-up table for fast path.
(initialize): Update 'asctobin' initialization.
(radix64_read): Add fast path for radix64 to binary conversion.
--

This patch adds fast path for radix64 to binary conversion in
armored 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
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+iobuf+crc+radix64 opt)
-------------------------------------
gpg process
armor: user time pipe transfer rate
decrypt-aead: 9.8 200 MB/s
decrypt-cfb: 11.9 168 MB/s

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
---
0 files changed

diff --git a/g10/armor.c b/g10/armor.c
index 95293d91c..972766503 100644
--- a/g10/armor.c
+++ b/g10/armor.c
@@ -40,7 +40,7 @@
static const byte bintoasc[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
-static byte asctobin[256]; /* runtime initialized */
+static u32 asctobin[4][256]; /* runtime initialized */
static int is_initialized;


@@ -171,11 +171,16 @@ initialize(void)
u32 i;
const byte *s;

- /* build the helptable for radix64 to bin conversion */
- for(i=0; i < 256; i++ )
- asctobin[i] = 255; /* used to detect invalid characters */
+ /* Build the helptable for radix64 to bin conversion. Value 0xffffffff is
+ used to detect invalid characters. */
+ memset (asctobin, 0xff, sizeof(asctobin));
for(s=bintoasc,i=0; *s; s++,i++ )
- asctobin[*s] = i;
+ {
+ asctobin[0][*s] = i << (0 * 6);
+ asctobin[1][*s] = i << (1 * 6);
+ asctobin[2][*s] = i << (2 * 6);
+ asctobin[3][*s] = i << (3 * 6);
+ }

is_initialized=1;
}
@@ -802,11 +807,13 @@ radix64_read( armor_filter_context_t *afx, IOBUF a, size_t *retn,
byte *buf, size_t size )
{
byte val;
- int c, c2;
+ int c;
+ u32 binc;
int checkcrc=0;
int rc = 0;
size_t n = 0;
- int idx, onlypad=0;
+ int idx, onlypad=0;
+ int skip_fast = 0;

idx = afx->idx;
val = afx->radbuf[0];
@@ -827,6 +834,122 @@ radix64_read( armor_filter_context_t *afx, IOBUF a, size_t *retn,
}

again:
+ binc = asctobin[0][c];
+
+ if( binc != 0xffffffffUL )
+ {
+ if( idx == 0 && skip_fast == 0
+ && afx->buffer_pos + (16 - 1) < afx->buffer_len
+ && n + 12 < size)
+ {
+ /* Fast path for radix64 to binary conversion. */
+ u32 b0,b1,b2,b3;
+
+ /* Speculatively load 15 more input bytes. */
+ b0 = binc << (3 * 6);
+ b0 |= asctobin[2][afx->buffer[afx->buffer_pos + 0]];
+ b0 |= asctobin[1][afx->buffer[afx->buffer_pos + 1]];
+ b0 |= asctobin[0][afx->buffer[afx->buffer_pos + 2]];
+ b1 = asctobin[3][afx->buffer[afx->buffer_pos + 3]];
+ b1 |= asctobin[2][afx->buffer[afx->buffer_pos + 4]];
+ b1 |= asctobin[1][afx->buffer[afx->buffer_pos + 5]];
+ b1 |= asctobin[0][afx->buffer[afx->buffer_pos + 6]];
+ b2 = asctobin[3][afx->buffer[afx->buffer_pos + 7]];
+ b2 |= asctobin[2][afx->buffer[afx->buffer_pos + 8]];
+ b2 |= asctobin[1][afx->buffer[afx->buffer_pos + 9]];
+ b2 |= asctobin[0][afx->buffer[afx->buffer_pos + 10]];
+ b3 = asctobin[3][afx->buffer[afx->buffer_pos + 11]];
+ b3 |= asctobin[2][afx->buffer[afx->buffer_pos + 12]];
+ b3 |= asctobin[1][afx->buffer[afx->buffer_pos + 13]];
+ b3 |= asctobin[0][afx->buffer[afx->buffer_pos + 14]];
+
+ /* Check if any of the input bytes were invalid. */
+ if( (b0 | b1 | b2 | b3) != 0xffffffffUL )
+ {
+ /* All 16 bytes are valid. */
+ buf[n + 0] = b0 >> (2 * 8);
+ buf[n + 1] = b0 >> (1 * 8);
+ buf[n + 2] = b0 >> (0 * 8);
+ buf[n + 3] = b1 >> (2 * 8);
+ buf[n + 4] = b1 >> (1 * 8);
+ buf[n + 5] = b1 >> (0 * 8);
+ buf[n + 6] = b2 >> (2 * 8);
+ buf[n + 7] = b2 >> (1 * 8);
+ buf[n + 8] = b2 >> (0 * 8);
+ buf[n + 9] = b3 >> (2 * 8);
+ buf[n + 10] = b3 >> (1 * 8);
+ buf[n + 11] = b3 >> (0 * 8);
+ afx->buffer_pos += 16 - 1;
+ n += 12;
+ continue;
+ }
+ else if( b0 == 0xffffffffUL )
+ {
+ /* byte[1..3] have invalid character(s). Switch to slow
+ path. */
+ skip_fast = 1;
+ }
+ else if( b1 == 0xffffffffUL )
+ {
+ /* byte[4..7] have invalid character(s), first 4 bytes are
+ valid. */
+ buf[n + 0] = b0 >> (2 * 8);
+ buf[n + 1] = b0 >> (1 * 8);
+ buf[n + 2] = b0 >> (0 * 8);
+ afx->buffer_pos += 4 - 1;
+ n += 3;
+ skip_fast = 1;
+ continue;
+ }
+ else if( b2 == 0xffffffffUL )
+ {
+ /* byte[8..11] have invalid character(s), first 8 bytes are
+ valid. */
+ buf[n + 0] = b0 >> (2 * 8);
+ buf[n + 1] = b0 >> (1 * 8);
+ buf[n + 2] = b0 >> (0 * 8);
+ buf[n + 3] = b1 >> (2 * 8);
+ buf[n + 4] = b1 >> (1 * 8);
+ buf[n + 5] = b1 >> (0 * 8);
+ afx->buffer_pos += 8 - 1;
+ n += 6;
+ skip_fast = 1;
+ continue;
+ }
+ else /*if( b3 == 0xffffffffUL )*/
+ {
+ /* byte[12..15] have invalid character(s), first 12 bytes
+ are valid. */
+ buf[n + 0] = b0 >> (2 * 8);
+ buf[n + 1] = b0 >> (1 * 8);
+ buf[n + 2] = b0 >> (0 * 8);
+ buf[n + 3] = b1 >> (2 * 8);
+ buf[n + 4] = b1 >> (1 * 8);
+ buf[n + 5] = b1 >> (0 * 8);
+ buf[n + 6] = b2 >> (2 * 8);
+ buf[n + 7] = b2 >> (1 * 8);
+ buf[n + 8] = b2 >> (0 * 8);
+ afx->buffer_pos += 12 - 1;
+ n += 9;
+ skip_fast = 1;
+ continue;
+ }
+ }
+
+ switch(idx)
+ {
+ case 0: val = binc << 2; break;
+ case 1: val |= (binc>>4)&3; buf[n++]=val;val=(binc<<4)&0xf0;break;
+ case 2: val |= (binc>>2)&15; buf[n++]=val;val=(binc<<6)&0xc0;break;
+ case 3: val |= binc&0x3f; buf[n++] = val; break;
+ }
+ idx = (idx+1) % 4;
+
+ continue;
+ }
+
+ skip_fast = 0;
+
if( c == '\n' || c == ' ' || c == '\r' || c == '\t' )
continue;
else if( c == '=' ) { /* pad character: stop */
@@ -857,10 +980,10 @@ radix64_read( armor_filter_context_t *afx, IOBUF a, size_t *retn,
if (afx->buffer_pos + 6 < afx->buffer_len
&& afx->buffer[afx->buffer_pos + 0] == '3'
&& afx->buffer[afx->buffer_pos + 1] == 'D'
- && asctobin[afx->buffer[afx->buffer_pos + 2]] != 255
- && asctobin[afx->buffer[afx->buffer_pos + 3]] != 255
- && asctobin[afx->buffer[afx->buffer_pos + 4]] != 255
- && asctobin[afx->buffer[afx->buffer_pos + 5]] != 255
+ && asctobin[0][afx->buffer[afx->buffer_pos + 2]] != 0xffffffffUL
+ && asctobin[0][afx->buffer[afx->buffer_pos + 3]] != 0xffffffffUL
+ && asctobin[0][afx->buffer[afx->buffer_pos + 4]] != 0xffffffffUL
+ && asctobin[0][afx->buffer[afx->buffer_pos + 5]] != 0xffffffffUL
&& afx->buffer[afx->buffer_pos + 6] == '\n')
{
afx->buffer_pos += 2;
@@ -875,17 +998,10 @@ radix64_read( armor_filter_context_t *afx, IOBUF a, size_t *retn,
checkcrc++;
break;
}
- else if( (c = asctobin[(c2=c)]) == 255 ) {
- log_error(_("invalid radix64 character %02X skipped\n"), c2);
+ else {
+ log_error(_("invalid radix64 character %02X skipped\n"), c);
continue;
}
- switch(idx) {
- case 0: val = c << 2; break;
- case 1: val |= (c>>4)&3; buf[n++]=val;val=(c<<4)&0xf0;break;
- case 2: val |= (c>>2)&15; buf[n++]=val;val=(c<<6)&0xc0;break;
- case 3: val |= c&0x3f; buf[n++] = val; break;
- }
- idx = (idx+1) % 4;
}

afx->idx = idx;
@@ -924,13 +1040,13 @@ radix64_read( armor_filter_context_t *afx, IOBUF a, size_t *retn,
u32 mycrc = 0;
idx = 0;
do {
- if( (c = asctobin[c]) == 255 )
+ if( (binc = asctobin[0][c]) == 0xffffffffUL )
break;
switch(idx) {
- case 0: val = c << 2; break;
- case 1: val |= (c>>4)&3; mycrc |= val << 16;val=(c<<4)&0xf0;break;
- case 2: val |= (c>>2)&15; mycrc |= val << 8;val=(c<<6)&0xc0;break;
- case 3: val |= c&0x3f; mycrc |= val; break;
+ case 0: val = binc << 2; break;
+ case 1: val |= (binc>>4)&3; mycrc |= val << 16;val=(binc<<4)&0xf0;break;
+ case 2: val |= (binc>>2)&15; mycrc |= val << 8;val=(binc<<6)&0xc0;break;
+ case 3: val |= binc&0x3f; mycrc |= val; break;
}
for(;;) {
if( afx->buffer_pos < afx->buffer_len )


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