9 docs tagged with "profiling"

Why this matters

Why this matters

Nsight Systems narrows a slow run down to a slow kernel; Nsight Compute is what explains why that one kernel is slow. It replays the kernel with hardware performance counters attached and organizes the results into sections that go from a two-number summary down to per-source-line detail, which is the tool The Optimization Workflow means by "measure first."

Nsight Systems answers "where does the wall-clock time go across CPU, GPU, memory, and the network"; Nsight Compute answers "why is this one kernel slow" — start with Systems, because a kernel that looks slow in isolation is sometimes just waiting behind something else, and no amount of kernel-level tuning fixes a scheduling gap.

Tools for finding performance bottlenecks: CPU time, cache misses, branch mispredictions. Measure first, then optimize.

Why this matters

Tuning a kernel without a loop around the work turns into guessing: try something that sounds plausible, rerun, eyeball whether it got faster, repeat. The workflow that actually converges is narrower than that — profile to find the one resource the kernel is actually waiting on, apply only the fix that targets that resource, re-measure to confirm the fix worked and see what limiter is binding now, and stop once further gains are no longer worth the effort. Every other page in this folder is a toolbox entry for one step of this loop, not a replacement for it.

Why this matters

Dynamic analysis tool suite for memory debugging, leak detection, and profiling. More thorough than sanitizers but much slower (10-50x).