diff options
| -rw-r--r-- | src/xz/args.c | 18 | ||||
| -rw-r--r-- | src/xz/hardware.c | 17 | ||||
| -rw-r--r-- | src/xz/hardware.h | 1 | ||||
| -rw-r--r-- | src/xz/xz.1 | 21 |
4 files changed, 51 insertions, 6 deletions
diff --git a/src/xz/args.c b/src/xz/args.c index 639c811a..8953aa59 100644 --- a/src/xz/args.c +++ b/src/xz/args.c @@ -258,11 +258,23 @@ parse_real(args_info *args, int argc, char **argv) suffix_set(optarg); break; - case 'T': + case 'T': { + // Since xz 5.4.0: Ignore leading '+' first. + const char *s = optarg; + if (optarg[0] == '+') + ++s; + // The max is from src/liblzma/common/common.h. - hardware_threads_set(str_to_uint64("threads", - optarg, 0, 16384)); + uint32_t t = str_to_uint64("threads", s, 0, 16384); + + // If leading '+' was used then use multi-threaded + // mode even if exactly one thread was specified. + if (t == 1 && optarg[0] == '+') + t = UINT32_MAX; + + hardware_threads_set(t); break; + } // --version case 'V': diff --git a/src/xz/hardware.c b/src/xz/hardware.c index 1fdecea1..97f77f80 100644 --- a/src/xz/hardware.c +++ b/src/xz/hardware.c @@ -21,6 +21,10 @@ static uint32_t threads_max = 1; /// on the available hardware threads. static bool threads_are_automatic = false; +/// If true, then try to use multi-threaded mode (if memlimit allows) +/// even if only one thread was requested explicitly (-T+1). +static bool use_mt_mode_with_one_thread = false; + /// Memory usage limit for compression static uint64_t memlimit_compress = 0; @@ -57,9 +61,16 @@ static uint64_t total_ram; extern void hardware_threads_set(uint32_t n) { + // Reset these to false first and set them to true when appropriate. + threads_are_automatic = false; + use_mt_mode_with_one_thread = false; + if (n == 0) { // Automatic number of threads was requested. + // If there is only one hardware thread, multi-threaded + // mode will still be used if memory limit allows. threads_are_automatic = true; + use_mt_mode_with_one_thread = true; // If threading support was enabled at build time, // use the number of available CPU cores. Otherwise @@ -72,9 +83,11 @@ hardware_threads_set(uint32_t n) #else threads_max = 1; #endif + } else if (n == UINT32_MAX) { + use_mt_mode_with_one_thread = true; + threads_max = 1; } else { threads_max = n; - threads_are_automatic = false; } return; @@ -92,7 +105,7 @@ extern bool hardware_threads_is_mt(void) { #ifdef MYTHREAD_ENABLED - return threads_max > 1 || threads_are_automatic; + return threads_max > 1 || use_mt_mode_with_one_thread; #else return false; #endif diff --git a/src/xz/hardware.h b/src/xz/hardware.h index 2cd6aa23..2bb3d7ba 100644 --- a/src/xz/hardware.h +++ b/src/xz/hardware.h @@ -16,6 +16,7 @@ extern void hardware_init(void); /// Set the maximum number of worker threads. +/// A special value of UINT32_MAX sets one thread in multi-threaded mode. extern void hardware_threads_set(uint32_t threadlimit); /// Get the maximum number of worker threads. diff --git a/src/xz/xz.1 b/src/xz/xz.1 index 62bab507..1ff110e8 100644 --- a/src/xz/xz.1 +++ b/src/xz/xz.1 @@ -5,7 +5,7 @@ .\" This file has been put into the public domain. .\" You can do whatever you want with this file. .\" -.TH XZ 1 "2022-11-09" "Tukaani" "XZ Utils" +.TH XZ 1 "2022-11-19" "Tukaani" "XZ Utils" . .SH NAME xz, unxz, xzcat, lzma, unlzma, lzcat \- Compress or decompress .xz and .lzma files @@ -1214,6 +1214,25 @@ even if the system supports only one hardware thread. 5.2.x used single-threaded mode in this situation.) .IP "" +To use multi-threaded mode with only one thread, set +.I threads +to +.BR +1 . +The +.B + +prefix has no effect with values other than +.BR 1 . +A memory usage limit can still make +.B xz +switch to single-threaded mode unless +.B \-\-no\-adjust +is used. +Support for the +.B + +prefix was added in +.B xz +5.4.0. +.IP "" If an automatic number of threads has been requested and no memory usage limit has been specified, then a system-specific default soft limit will be used to possibly |