mirror of
https://git.tukaani.org/xz.git
synced 2024-04-04 12:36:23 +02:00
Docs: Use lzma_cputhreads() in 04_compress_easy_mt.c.
This commit is contained in:
parent
8dbb57238d
commit
cbafa71091
1 changed files with 26 additions and 4 deletions
|
@ -31,10 +31,6 @@ init_encoder(lzma_stream *strm)
|
|||
// No flags are needed.
|
||||
.flags = 0,
|
||||
|
||||
// Set the number of threads to use.
|
||||
// FIXME: Add how to autodetect a reasonable number.
|
||||
.threads = 4,
|
||||
|
||||
// Let liblzma determine a sane block size.
|
||||
.block_size = 0,
|
||||
|
||||
|
@ -57,6 +53,32 @@ init_encoder(lzma_stream *strm)
|
|||
.check = LZMA_CHECK_CRC64,
|
||||
};
|
||||
|
||||
// Detect how many threads the CPU supports.
|
||||
mt.threads = lzma_cputhreads();
|
||||
|
||||
// If the number of CPU cores/threads cannot be detected,
|
||||
// use one thread. Note that this isn't the same as the normal
|
||||
// single-threaded mode as this will still split the data into
|
||||
// blocks and use more RAM than the normal single-threaded mode.
|
||||
// You may want to consider using lzma_easy_encoder() or
|
||||
// lzma_stream_encoder() instead of lzma_stream_encoder_mt() if
|
||||
// lzma_cputhreads() returns 0 or 1.
|
||||
if (mt.threads == 0)
|
||||
mt.threads = 1;
|
||||
|
||||
// If the number of CPU cores/threads exceeds threads_max,
|
||||
// limit the number of threads to keep memory usage lower.
|
||||
// The number 8 is arbitrarily chosen and may be too low or
|
||||
// high depending on the compression preset and the computer
|
||||
// being used.
|
||||
//
|
||||
// FIXME: A better way could be to check the amount of RAM
|
||||
// (or available RAM) and use lzma_stream_encoder_mt_memusage()
|
||||
// to determine if the number of threads should be reduced.
|
||||
const uint32_t threads_max = 8;
|
||||
if (mt.threads > threads_max)
|
||||
mt.threads = threads_max;
|
||||
|
||||
// Initialize the threaded encoder.
|
||||
lzma_ret ret = lzma_stream_encoder_mt(strm, &mt);
|
||||
|
||||
|
|
Loading…
Reference in a new issue