Take page size into account.

src/collect/mod.rs

@@ -2,7 +2,8 @@
 
 use crate::{errors::HWTracerError, Trace};
 use core::arch::x86_64::__cpuid_count;
-use libc::size_t;
+use libc::{size_t, sysconf, _SC_PAGESIZE};
+use std::{convert::TryFrom, sync::LazyLock};
 use strum::IntoEnumIterator;
 use strum_macros::EnumIter;
 
@@ -12,7 +13,13 @@ pub(crate) mod perf;
 pub(crate) use perf::PerfTraceCollector;
 
 const PERF_DFLT_DATA_BUFSIZE: size_t = 64;
-const PERF_DFLT_AUX_BUFSIZE: size_t = 16384; // 64MiB if the page size is 4096 bytes.
+const PERF_DFLT_AUX_BUFSIZE: LazyLock<size_t> = LazyLock::new(|| {
+    // Allocate enough pages for a 64MiB trace buffer.
+    let mb64 = 1024 * 1024 * 64;
+    let page_sz = size_t::try_from(unsafe { sysconf(_SC_PAGESIZE) }).unwrap();
+    mb64 / page_sz + size_t::from(mb64 % page_sz != 0)
+});
+
 const PERF_DFLT_INITIAL_TRACE_BUFSIZE: size_t = 1024 * 1024; // 1MiB
 
 /// The interface offered by all trace collectors.
@@ -100,7 +107,7 @@ impl Default for PerfCollectorConfig {
     fn default() -> Self {
         Self {
             data_bufsize: PERF_DFLT_DATA_BUFSIZE,
-            aux_bufsize: PERF_DFLT_AUX_BUFSIZE,
+            aux_bufsize: *PERF_DFLT_AUX_BUFSIZE,
             initial_trace_bufsize: PERF_DFLT_INITIAL_TRACE_BUFSIZE,
         }
     }

src/lib.rs

@@ -1,5 +1,6 @@
 #![allow(clippy::upper_case_acronyms)]
 #![allow(clippy::new_without_default)]
+#![feature(once_cell)]
 
 mod block;
 pub use block::Block;