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changed Makefile variable HAVE_THREAD -> HAVE_MULTITHREAD

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and updated documentation `programs/README.md`
This commit is contained in:
Yann Collet 2024-07-06 01:55:50 -07:00
parent b5639ade0e
commit 04341f1974
2 changed files with 19 additions and 19 deletions
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4
programs/Makefile
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@ -66,8 +66,8 @@ ALLFLAGS = $(CFLAGS) $(CPPFLAGS) $(LDFLAGS)
NUM_SYMBOL := \#
NO_THREAD_MSG:= ==> no multithread support: building for single-thread mode only
HAVE_PTHREAD := $(shell printf '$(NUM_SYMBOL)include <pthread.h>\nint main(void) { return 0; }' > have_pthread.c && $(CC) $(ALLFLAGS) -o have_pthread$(EXT) have_pthread.c -pthread 2> $(VOID) && rm -f have_pthread$(EXT) && echo 1 || echo 0; rm have_pthread.c)
HAVE_THREAD := $(shell [ "$(HAVE_PTHREAD)" -eq "1" -o -n "$(filter Windows%,$(OS))" ] && echo 1 || echo 0)
ifeq ($(HAVE_THREAD), 1)
HAVE_MULTITHREAD := $(shell [ "$(HAVE_PTHREAD)" -eq "1" -o -n "$(filter Windows%,$(OS))" ] && echo 1 || echo 0)
ifeq ($(HAVE_MULTITHREAD), 1)
THREAD_MSG := ==> building with multithreading support
THREAD_CPP := -DLZ4IO_MULTITHREAD
ifeq ($(HAVE_PTHREAD), 1)

34
programs/README.md
View File

@ -2,7 +2,7 @@ Command Line Interface for LZ4 library
============================================
### Build
The Command Line Interface (CLI) is generated
The `lz4` Command Line Interface (CLI) is generated
using the `make` command, no additional parameter required.
The CLI generates and decodes [LZ4-compressed frames](../doc/lz4_Frame_format.md).
@ -19,35 +19,35 @@ The makefile offer several targets for various use cases:
- `unlz4`, `lz4cat` : symlinks to `lz4`, default to decompression and `cat` compressed files
- `man` : generates the man page, from `lz4.1.md` markdown source
#### Makefile Build variables
- `HAVE_MULTITHREAD` : build with multithreading support. Detection is generally automatic, but can be forced to `0` or `1` if needed. This is for example useful when cross-compiling for Windows from Linux.
- `HAVE_PTHREAD` : determines presence of `<pthread>` support. Detection is automatic, but can be forced to `0` or `1` if needed. This is in turn used by `make` to automatically trigger multithreading support.
#### C Preprocessor variables
These variables are read by the preprocessor at compilation time, they influence executable behavior, such as default starting values,
and are exposed from `programs/lz4conf.h`.
These variables are read by the preprocessor at compilation time. They influence executable behavior, such as default starting values, and are exposed from `programs/lz4conf.h`. These variables can modified by other build systems, such as `cmake`.
Assignment methods vary depending on environments.
On a typical `posix` + `gcc` + `make` setup, they can be defined with `CPPFLAGS=-DVARIABLE=value` assignment.
- `LZ4IO_MULTITHREAD`: enable multithreading support
- `LZ4IO_MULTITHREAD`: enable multithreading support. Default is disabled.
- `LZ4_NBTHREADS_DEFAULT`: default nb of threads in multithreading mode.
Default is `0`, which means "auto-determine" based on local cpu.
- `LZ4_BLOCKSIZEID_DEFAULT`: default `lz4` block size code. Valid values are [4-7].
#### Makefile Build variables
- `HAVE_THREAD` : determines usage of multithreading support. Detection is generally automatic, but can be forced to `0` or `1` if needed. This is for example useful when cross-compiling for Windows from Linux.
- `HAVE_PTHREAD` : determines presences of `<pthread>` support. This is in turn used by `make` to trigger multithreading support. Detection is automatic, but can be forced to `0` or `1` if needed.
- `LZ4_BLOCKSIZEID_DEFAULT`: default `lz4` block size code. Valid values are [4-7], corresponding to 64 KB, 256 KB, 1 MB and 4 MB. At the time of this writing, default is 7, corresponding to 4 MB block size.
### Aggregation of parameters
The `lz4` CLI supports aggregation for short commands. For example, `-b1`, `-e18`, and `-i1` can be joined into `-b1e18i1`.
This doesn't work for `--long-commands`, which must be separated.
The `lz4` CLI supports aggregation for short commands. For example, `-d`, `-q`, and `-f` can be joined into `-dqf`.
Aggregation doesn't work for `--long-commands`, which **must** be separated.
### Benchmark in Command Line Interface
CLI includes in-memory compression benchmark module for lz4.
The benchmark is conducted using a given filename.
The file is read into memory.
It makes benchmark more precise as it eliminates I/O overhead.
`lz4` CLI includes an in-memory compression benchmark module, triggered by command `-b#`, with `#` representing the compression level.
The benchmark is conducted on a provided list of filenames.
The files are then read entirely into memory, to eliminate I/O overhead.
When multiple files are provided, they are bundled into the same benchmark session (though each file is a separate compression / decompression). Using `-S` command separates them (one session per file).
When no file is provided, uses an internal Lorem Ipsum generator instead.
The benchmark measures ratio, compressed size, compression and decompression speed.
One can select compression levels starting from `-b` and ending with `-e`.
The `-i` parameter selects a number of seconds used for each of tested levels.
One can select multiple compression levels starting from `-b` and ending with `-e` (ascending).
The `-i` parameter selects a number of seconds used for each session.
### Usage of Command Line Interface