rt/snapraid
1
0
Fork 0
mirror of https://github.com/amadvance/snapraid.git synced 2026-10-26 19:01:57 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

Remove stream CRC and optimize CRC compute CRC32C using two lanes

Browse source
This commit is contained in:
Andrea Mazzoleni 2026-09-10 07:39:21 +02:00
parent 581ec4e156
commit a01ec45f14
7 changed files with 196 additions and 129 deletions
Download patch file Download diff file Expand all files Collapse all files

39
cmdline/stream.h
View file

@ -65,26 +65,6 @@ struct stream {
*/
uint32_t crc_uncached;
/**
* CRC of the data written to the stream.
*
* This is an extra check of the data that is written to
* file to ensure that it's consistent even in case
* of memory errors.
*
* This extra check takes about 2 seconds for each GB of
* content file with the Intel CRC instruction,
* and about 4 seconds without it.
* But usually this doesn't slow down the write process,
* as the disk is the bottle-neck.
*
* Note that this CRC doesn't have the IV processing.
*
* Not used in reading.
* In writing, it's all the data wrote calling sput() functions.
*/
uint32_t crc_stream;
struct advise_struct* advise; /**< Cache advice state for each handle. */
};
@ -147,11 +127,6 @@ int64_t stell(STREAM* s);
*/
uint32_t scrc(STREAM* s);
/**
* Get the CRC of the processed data in put.
*/
uint32_t scrc_stream(STREAM* s);
/**
* Check if the buffer has enough data loaded.
*/
@ -369,16 +344,6 @@ static inline int sputc(int c, STREAM* s)
return -1;
}
/**
* Update the crc *before* writing the data in the buffer
*
* This must be done before the memory write,
* to be able to detect memory errors on the buffer,
* happening before we write it on the file.
*/
if (s->flags & STREAM_FLAGS_CRC)
s->crc_stream = crc32c_plain_char(s->crc_stream, c);
*s->pos++ = c;
return 0;
@ -412,10 +377,6 @@ static __always_inline int swrite(const void* data, size_t size, STREAM* f)
if (tommy_unlikely(!sptrlookup(f, size)))
return swrite_uncached(data, size, f);
/* compute the independent CRC before copying to detect buffer corruption */
if (f->flags & STREAM_FLAGS_CRC)
f->crc_stream = crc32c_plain(f->crc_stream, data, size);
memcpy(f->pos, data, size);
f->pos += size;