forked from OSchip/llvm-project
09158252f7
Before this patch, it wasn't possible to extend the ThinLTO threads to all SMT/CMT threads in the system. Only one thread per core was allowed, instructed by usage of llvm::heavyweight_hardware_concurrency() in the ThinLTO code. Any number passed to the LLD flag /opt:lldltojobs=..., or any other ThinLTO-specific flag, was previously interpreted in the context of llvm::heavyweight_hardware_concurrency(), which means SMT disabled. One can now say in LLD: /opt:lldltojobs=0 -- Use one std::thread / hardware core in the system (no SMT). Default value if flag not specified. /opt:lldltojobs=N -- Limit usage to N threads, regardless of usage of heavyweight_hardware_concurrency(). /opt:lldltojobs=all -- Use all hardware threads in the system. Equivalent to /opt:lldltojobs=$(nproc) on Linux and /opt:lldltojobs=%NUMBER_OF_PROCESSORS% on Windows. When an affinity mask is set for the process, threads will be created only for the cores selected by the mask. When N > number-of-hardware-threads-in-the-system, the threads in the thread pool will be dispatched equally on all CPU sockets (tested only on Windows). When N <= number-of-hardware-threads-on-a-CPU-socket, the threads will remain on the CPU socket where the process started (only on Windows). Differential Revision: https://reviews.llvm.org/D75153 |
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| .. | ||
| COM.inc | ||
| DynamicLibrary.inc | ||
| Host.inc | ||
| Memory.inc | ||
| Path.inc | ||
| Process.inc | ||
| Program.inc | ||
| README.txt | ||
| Signals.inc | ||
| ThreadLocal.inc | ||
| Threading.inc | ||
| Unix.h | ||
| Watchdog.inc | ||
README.txt
llvm/lib/Support/Unix README =========================== This directory provides implementations of the lib/System classes that are common to two or more variants of UNIX. For example, the directory structure underneath this directory could look like this: Unix - only code that is truly generic to all UNIX platforms Posix - code that is specific to Posix variants of UNIX SUS - code that is specific to the Single Unix Specification SysV - code that is specific to System V variants of UNIX As a rule, only those directories actually needing to be created should be created. Also, further subdirectories could be created to reflect versions of the various standards. For example, under SUS there could be v1, v2, and v3 subdirectories to reflect the three major versions of SUS.