randomx: optional 2 MB large pages for the cache, dataset and scratchpads

RandomX reads its 256 MB cache, 2 GB dataset and per-VM scratchpads at random,
so most accesses miss the TLB on 4 KB pages. Requesting 2 MB pages recovers
roughly a tenth of the hash rate. Each allocation tries large pages first and
falls back to normal pages when the pool is not reserved, so nothing regresses
when hugepages are unavailable. -nolargepages opts out, and the diagnostics
report which allocations got large pages.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/randomx_pow.h b/src/randomx_pow.h
index 0027571..355b708 100644
--- a/src/randomx_pow.h
+++ b/src/randomx_pow.h
@@ -41,4 +41,11 @@ uint256 RandomXHashWithVM(void* vm, const void* pHeader, size_t nSize);
 // True when the 2 GB dataset is ready (fast mode active).
 bool RandomXFastReady();
 
+// Ask for large (2 MB) pages for the cache, dataset and scratchpads. Set false
+// by -nolargepages. Must be set before the first RandomXInit().
+extern bool fRandomXLargePages;
+
+// Which allocations actually got large pages, for the status display.
+const char* RandomXLargePagesStatus();
+
 #endif