solver benchmark: specifying solver-specific options

tutorials/introduction-to-solverbenchmark/index.jmd

@@ -221,3 +221,34 @@ p = profile_solvers(stats, costs, costnames)
 Here is a useful tutorial on how to use the benchmark with specific solver:
 [Run a benchmark with OptimizationProblems](https://jso.dev/OptimizationProblems.jl/dev/benchmark/)
 The tutorial covers how to use the problems from `OptimizationProblems` to run a benchmark for unconstrained optimization.
+
+## Handling `solver_specific` in benchmark runs
+
+`SolverBenchmark` accepts solver-specific options via the keyword argument `solver_specific` on benchmarking functions (for example, when calling the high-level benchmarking helpers such as `bmark_solvers`).
+
+- `solver_specific` is a mapping that associates a solver identifier (typically a `Symbol` or the solver name you use in the benchmark) with a dictionary of options specific to that solver implementation.
+- Those options are passed through to the solver when the run is executed and are recorded as part of the run metadata.
+- As a result, runs that differ only by solver-specific options are treated as distinct entries in the benchmark results; you can group, filter or compare them in the produced `DataFrame`s.
+
+```julia
+using SolverBenchmark, NLPModelsTest, JSOSolvers
+
+solver_specific = Dict(
+  :IPOPT => Dict("tol" => 1e-8, "max_iter" => 200),
+  :KNITRO => Dict("maxit" => 500)
+)
+
+results = bmark_solvers(solvers, problems; solver_specific = solver_specific)
+
+first(results)
+```
+
+Notes and tips:
+
+- If you pass different option sets for the same solver, make sure the keys you use
+  identify the intended solver variation unambiguously (e.g., distinct Symbols).
+- When creating tables or profiles, you can add or extract columns from the per-solver
+  DataFrames to show which solver-specific options were used for each run.
+- If you prefer the solver-specific settings to appear as explicit columns, you can
+  preprocess the DataFrames (extract the dict entries into columns) before creating
+  joined tables or profile plots.