Rewrite nvtaskset and implementation of partitioning for unmodified tasks

Rather than requiring libsmctrl.so to be preloaded, we now wrap
libcuda.so.1. All CUDA-using applications will load libcuda.so.1,
ensuring that our wrapper will always be dynamically loaded, no
matter if LD_PRELOAD is enabled, or if a program has been staticly
linked. All that needs to be done is that the location of our
"fake" libcuda.so.1 need to be put within the loader search path.
This can be done by setting LD_LIBRARY_PATH, or by installing
our wrapper into /lib/x86_64-linux-gnu.

The mask can still be set via the LIBSMCTRL_MASK environment
variable, but the easier-to-use nvtaskset tool is now the
recommended way to view or change the supreme TPC mask for any
CUDA-using application. This allows launching a program on the
first two GPCs via a command as simple as:
    ./nvtaskset -g 0-1 ./a_program a_program_args
(Note that use of the -g option requires the nvdebug kernel module
to first be loaded.)

These changes support the final version of the ECRTS'25 paper.

Note that nvtaskset does not yet fully support multi-GPU systems.

Bugfixes:
- Fix crash that would occur if both libsmctrl.so and libsmctrl.a
  were built into an application.
- Correctly use GPU ID when initializing a context in
  `libsmctrl_test_gpc_info`.
- Include `nvtaskset` as a prerequisite for
  `libsmctrl_test_supreme_mask`.
- Fix malfunction of `libsmctrl_test_gpc_info` if
  CUDA_VISIBLE_DEVICES is set.

Other minor changes:
- Adds make target to run all the tests.
- Fixes typos in comments.
- Enables -Wall build option.
- Upgrades supreme mask from 64 to 128 bits.
- Removes `detect_parker_soc()` from the global namespace.
- Adjusts test messages to be more succinct.
- Updates README with overview of how to partition unmodified
  applications, more details on the tests, and information on the
  new ECRTS'25 paper.

1 files changed, 3 insertions, 1 deletions

diff --git a/libsmctrl_test_gpc_info.c b/libsmctrl_test_gpc_info.c
index 558b80a..afa0876 100644
--- a/libsmctrl_test_gpc_info.c
+++ b/libsmctrl_test_gpc_info.c
@@ -38,6 +38,8 @@ int main(int argc, char** argv) {
                 gpu_id = 0;
         // Tell CUDA to use PCI device id ordering (to match nvdebug)
         putenv((char*)"CUDA_DEVICE_ORDER=PCI_BUS_ID");
+        // Allow CUDA to see all devices (to better match nvdebug)
+        unsetenv("CUDA_VISIBLE_DEVICES");
         // A CUDA context is required before reading the topology information
         if ((res = cuInit(0))) {
                 const char* name;
@@ -45,7 +47,7 @@ int main(int argc, char** argv) {
                 fprintf(stderr, "%s: Unable to initialize CUDA, error %s\n", program_invocation_name, name);
                 return 1;
         }
-        if ((res = cuCtxCreate(&ctx, 0, 0))) {
+        if ((res = cuCtxCreate(&ctx, 0, gpu_id))) {
                 const char* name;
                 cuGetErrorName(res, &name);
                 fprintf(stderr, "%s: Unable to create a CUDA context, error %s\n", program_invocation_name, name);