diff --git a/Modules/CPack.cmake b/Modules/CPack.cmake
index 3b29ede644d3028912c7d668bfe566eb97671589..373a707308e610558b82ea660579765e28b38ccc 100644
--- a/Modules/CPack.cmake
+++ b/Modules/CPack.cmake
@@ -291,13 +291,21 @@ installers. The most commonly-used variables are:
Some compression methods used by CPack generators such as Debian or Archive
may take advantage of multiple CPU cores to speed up compression.
- ``CPACK_THREADS`` can be set to positive integer to specify how many threads
- will be used for compression. If it is set to 0, CPack will set it so that
- all available CPU cores are used.
+ ``CPACK_THREADS`` can be set to specify how many threads will be
+ used for compression.
+
+ A positive integer can be used to specify an exact desired thread count.
+
+ When given a negative integer CPack will use the absolute value
+ as the upper limit but may choose a lower value based on
+ the available hardware concurrency.
+
+ Given 0 CPack will try to use all available CPU cores.
+
By default ``CPACK_THREADS`` is set to ``1``.
- Currently only ``xz`` compression *may* take advantage of multiple cores. Other
- compression methods ignore this value and use only one thread.
+ Currently only ``xz`` compression *may* take advantage of multiple cores.
+ Other compression methods ignore this value and use only one thread.
.. versionadded:: 3.21
diff --git a/Source/CPack/cmCPackArchiveGenerator.cxx b/Source/CPack/cmCPackArchiveGenerator.cxx
index 7fd12dd4c12a78df93d217849ac780a8380e36e8..d9234e666999c0b59baed0032cb138649ff0d5db 100644
--- a/Source/CPack/cmCPackArchiveGenerator.cxx
+++ b/Source/CPack/cmCPackArchiveGenerator.cxx
@@ -2,14 +2,13 @@
file Copyright.txt or https://cmake.org/licensing for details. */
#include "cmCPackArchiveGenerator.h"
+#include <cstdlib>
#include <cstring>
#include <map>
#include <ostream>
#include <utility>
#include <vector>
-#include <cm3p/archive.h>
-
#include "cmCPackComponentGroup.h"
#include "cmCPackGenerator.h"
#include "cmCPackLog.h"
@@ -154,15 +153,9 @@ int cmCPackArchiveGenerator::addOneComponentToArchive(
<< (filename) << ">." << std::endl); \
return 0; \
} \
- cmArchiveWrite archive(gf, this->Compress, this->ArchiveFormat); \
+ cmArchiveWrite archive(gf, this->Compress, this->ArchiveFormat, 0, \
+ this->GetThreadCount()); \
do { \
- if (!this->SetArchiveOptions(&archive)) { \
- cmCPackLogger(cmCPackLog::LOG_ERROR, \
- "Problem to set archive options <" \
- << (filename) << ">, ERROR = " << (archive).GetError() \
- << std::endl); \
- return 0; \
- } \
if (!archive.Open()) { \
cmCPackLogger(cmCPackLog::LOG_ERROR, \
"Problem to open archive <" \
@@ -346,26 +339,16 @@ bool cmCPackArchiveGenerator::SupportsComponentInstallation() const
return this->IsOn("CPACK_ARCHIVE_COMPONENT_INSTALL");
}
-bool cmCPackArchiveGenerator::SetArchiveOptions(cmArchiveWrite* archive)
+int cmCPackArchiveGenerator::GetThreadCount() const
{
-#if ARCHIVE_VERSION_NUMBER >= 3004000
- // Upstream fixed an issue with their integer parsing in 3.4.0 which would
- // cause spurious errors to be raised from `strtoull`.
- if (this->Compress == cmArchiveWrite::CompressXZ) {
- const char* threads = "1";
-
- // CPACK_ARCHIVE_THREADS overrides CPACK_THREADS
- if (this->IsSet("CPACK_ARCHIVE_THREADS")) {
- threads = this->GetOption("CPACK_ARCHIVE_THREADS");
- } else if (this->IsSet("CPACK_THREADS")) {
- threads = this->GetOption("CPACK_THREADS");
- }
+ int threads = 1;
- if (!archive->SetFilterOption("xz", "threads", threads)) {
- return false;
- }
+ // CPACK_ARCHIVE_THREADS overrides CPACK_THREADS
+ if (this->IsSet("CPACK_ARCHIVE_THREADS")) {
+ threads = std::atoi(this->GetOption("CPACK_ARCHIVE_THREADS"));
+ } else if (this->IsSet("CPACK_THREADS")) {
+ threads = std::atoi(this->GetOption("CPACK_THREADS"));
}
-#endif
- return true;
+ return threads;
}
diff --git a/Source/CPack/cmCPackArchiveGenerator.h b/Source/CPack/cmCPackArchiveGenerator.h
index 5b40013b4a7dbe516714eafcf0afe646203b8b39..8a9bbc66b590449113f1a31dd804fec1567f712e 100644
--- a/Source/CPack/cmCPackArchiveGenerator.h
+++ b/Source/CPack/cmCPackArchiveGenerator.h
@@ -85,7 +85,7 @@ private:
return this->OutputExtension.c_str();
}
- bool SetArchiveOptions(cmArchiveWrite* archive);
+ int GetThreadCount() const;
private:
cmArchiveWrite::Compress Compress;
diff --git a/Source/CPack/cmCPackDebGenerator.cxx b/Source/CPack/cmCPackDebGenerator.cxx
index e7bcfaca4faa11fe4fd999fb663729d139873949..0fafd856ce39c34b666116bcdc3464cb0d864eb0 100644
--- a/Source/CPack/cmCPackDebGenerator.cxx
+++ b/Source/CPack/cmCPackDebGenerator.cxx
@@ -130,11 +130,6 @@ DebGenerator::DebGenerator(
"Unrecognized number of threads: " << numThreads
<< std::endl);
}
-
- if (this->NumThreads < 0) {
- cmCPackLogger(cmCPackLog::LOG_ERROR,
- "Number of threads cannot be negative" << std::endl);
- }
}
bool DebGenerator::generate() const
diff --git a/Source/cmArchiveWrite.cxx b/Source/cmArchiveWrite.cxx
index b685b73af8ee2bad0f9d524c2bc5ce46c1fc59d0..54b29982468a2c134c32761d1cddc9716da3dbd6 100644
--- a/Source/cmArchiveWrite.cxx
+++ b/Source/cmArchiveWrite.cxx
@@ -2,11 +2,16 @@
file Copyright.txt or https://cmake.org/licensing for details. */
#include "cmArchiveWrite.h"
-#include <cstdio>
+#include <cstdlib>
#include <cstring>
#include <ctime>
#include <iostream>
+#include <limits>
#include <sstream>
+#include <string>
+#include <thread>
+
+#include <cm/algorithm>
#include <cm3p/archive.h>
#include <cm3p/archive_entry.h>
@@ -144,16 +149,36 @@ cmArchiveWrite::cmArchiveWrite(std::ostream& os, Compress c,
cm_archive_error_string(this->Archive));
return;
}
+
{
- char sNumThreads[8];
- snprintf(sNumThreads, sizeof(sNumThreads), "%d", numThreads);
- sNumThreads[7] = '\0'; // for safety
+#if ARCHIVE_VERSION_NUMBER >= 3004000
+ // Upstream fixed an issue with their integer parsing in 3.4.0
+ // which would cause spurious errors to be raised from `strtoull`.
+
+ if (numThreads < 1) {
+ int upperLimit = (numThreads == 0) ? std::numeric_limits<int>::max()
+ : std::abs(numThreads);
+
+ numThreads =
+ cm::clamp<int>(std::thread::hardware_concurrency(), 1, upperLimit);
+ }
+
+# ifdef _AIX
+ // FIXME: Using more than 2 threads creates an empty archive.
+ // Enforce this limit pending further investigation.
+ numThreads = std::min(numThreads, 2);
+# endif
+
+ std::string sNumThreads = std::to_string(numThreads);
+
if (archive_write_set_filter_option(this->Archive, "xz", "threads",
- sNumThreads) != ARCHIVE_OK) {
+ sNumThreads.c_str()) !=
+ ARCHIVE_OK) {
this->Error = cmStrCat("archive_compressor_xz_options: ",
cm_archive_error_string(this->Archive));
return;
}
+#endif
}
break;
@@ -425,16 +450,3 @@ bool cmArchiveWrite::AddData(const char* file, size_t size)
}
return true;
}
-
-bool cmArchiveWrite::SetFilterOption(const char* module, const char* key,
- const char* value)
-{
- if (archive_write_set_filter_option(this->Archive, module, key, value) !=
- ARCHIVE_OK) {
- this->Error = "archive_write_set_filter_option: ";
- this->Error += cm_archive_error_string(this->Archive);
- return false;
- }
-
- return true;
-}
diff --git a/Source/cmArchiveWrite.h b/Source/cmArchiveWrite.h
index 34aafe905cd3d91900374982fd2fec4cd9c4bb3d..260bd20caae1462427e43910bc87ee4a89b308b0 100644
--- a/Source/cmArchiveWrite.h
+++ b/Source/cmArchiveWrite.h
@@ -141,9 +141,6 @@ public:
this->Gname = "";
}
- //! Set an option on a filter;
- bool SetFilterOption(const char* module, const char* key, const char* value);
-
private:
bool Okay() const { return this->Error.empty(); }
bool AddPath(const char* path, size_t skip, const char* prefix,
diff --git a/Tests/RunCMake/CPack/tests/THREADED_ALL/test.cmake b/Tests/RunCMake/CPack/tests/THREADED_ALL/test.cmake
index 6f37201311811ca5021dabbf70f098610e28c798..af39e5f2c9179b6e7403ad414ee27079e3e7e1cd 100644
--- a/Tests/RunCMake/CPack/tests/THREADED_ALL/test.cmake
+++ b/Tests/RunCMake/CPack/tests/THREADED_ALL/test.cmake
@@ -1,6 +1,6 @@
install(FILES CMakeLists.txt DESTINATION foo COMPONENT test)
-set(CPACK_THREADS 0)
+set(CPACK_THREADS "-4")
if(PACKAGING_TYPE STREQUAL "COMPONENT")
set(CPACK_COMPONENTS_ALL test)