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pinthread

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pinthread

pinthread is a little library intended for use with LD_PRELOAD environment var.

I've wrote it cause in devuan we intesively use qemu-static to build packages for different archs, but it doesn't work well with some processes using threads when the base host is multicore, so, this library will override the pthread_create() call and will pin the threads and the main process to run only on a specific core, making qemu happy and avoiding a lot of segfaults.

Build:

just type make and, optionally, make install

It will build a library (pinthread.so) and a binary (dotprod_mutex)

dotprod_mutex is just a test binary you can use for testing the library.

Usage:

LD_PRELOAD=/path/to/pinthread.so [binary_to_launch]

Environment variables:

  • PINTHREAD_CORE: set to the core number you want to pin to. if omitted, it defaults to the result of sched_getcpu()

  • PINTHREAD_PNAMES: accept a space separated list of strings, if any string match the process name or PINTHREAD_PNAMES is empty/omitted, it will pin all thread according to PINTHREAD_CORE, otherwise it will just call the "real" pthread_create without any pinning.

Known bugs:

When used in qemu-static for arm* architectures setting PINTHREAD_CORE is mandatory as internally we use the sched_getcpu() syscall that isn't (yet?) supported in qemu.