Datenrennen mit racecheck aufspüren

A data race happens when two threads touch the same shared memory and at least one writes, without ordering between them. 😬

Races often give the right answer in testing and the wrong one in production, because the result depends on unpredictable thread timing.

The racecheck tool of compute-sanitizer analyzes shared memory accesses and reports hazards that a normal run would hide.

Writing to a shared array and then reading a neighbor's slot without a barrier creates a race, since the neighbor may not be written yet.

Insert __syncthreads between the write and the read so every thread in the block finishes writing before anyone reads.

racecheck also catches a write-after-write hazard, where two threads store to the same shared slot with no order between them.

The most common hazard is read-after-write: a thread reads a value another thread is still writing, so it reads stale data.

racecheck names the hazard type plus the two threads and shared address involved, so you know exactly which barrier is missing.

racecheck focuses on __shared__ memory within a block; global races usually need careful logic or atomics instead.

Just like memcheck, compiling with -lineinfo lets racecheck point at the precise source line of each hazard.

Rerun racecheck after adding the barrier. A report of zero hazards means your shared-memory access is now properly ordered.

What is the usual fix when racecheck reports a shared-memory hazard?

You used racecheck to find shared-memory hazards, read its reports, and fixed them with __syncthreads barriers. Timing bugs, exposed. 🎯