2 files changed, 21 insertions, 0 deletions

diff --git a/doc/h48.md b/doc/h48.md
index 2487aad..d9ef192 100644
--- a/doc/h48.md
+++ b/doc/h48.md
@@ -225,6 +225,8 @@ of 1, 2 or 3 can be used directly as a lower bound of b+1, b+2 and b+3
 respectively. However, a value of 0 could mean that the actual lower
 bound is anything between 0 and b, so we cannot take b as a lower bound.
 
+#### Fallback tables
+
 To be able to still use some sort of pruning value even when we get a
 0 read, we use a **fallback table**. Inspired by nxopt, this table is
 interleaved with the main table for cache efficiency: every 254 entries
@@ -235,6 +237,16 @@ when looking up the minimum value in the fallback table after a 0 read.
 Smaller lines (of 256 or 128 bits) have been tried, but they do not
 give any significant improvement over 512 bit lines.
 
+This trick provides the gratest performance benefits if the main pruning
+table is properly aligned. Unfortunately, as a design choice, the
+solver is implemented here as a library that defer all memory allocation
+business to the implementor. We do make sure that the table is properly
+aligned in the programs provided in this repository (for example, the
+rudimentary shell and the tools), but we do not enforce this in the
+main library code.
+
+#### Additional (fast) lookups
+
 Moreover, as an additional heuristic, in case of a 0 read we also look
 up another pruning value in a table that takes into account only the
 position of the edges. This table is small (around 1MB), so repeated
diff --git a/doc/solvers.md b/doc/solvers.md
index a246c54..837cec6 100644
--- a/doc/solvers.md
+++ b/doc/solvers.md
@@ -16,6 +16,15 @@ about how this solver works, see [h48.md](./h48.md). For benchmarks see
 * Moveset: HTM (all 18 basic moves).
 * From 115MB to 59GB (roughly 2<sup>X</sup>*56MB).
 
+*Note: for better performance, the solver's data should be 64-byte
+aligned. To achieve this, one can use
+[`aligned_alloc(64, size)`](https://en.cppreference.com/w/c/memory/aligned_alloc)
+in C11 or later,
+[`_aligned_malloc(size, 64)`](https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/aligned-malloc)
+on Windows platforms, or the
+[aligned `new` operator](https://cppreference.com/w/cpp/memory/new/operator_new.html)
+in C++17 or later.*
+
 ## Coordinate solvers
 
 Various solvers to solve different substeps, commonly used for Fewest