diff --git a/README.md b/README.md
index c5c2dd8..750fd12 100644
--- a/README.md
+++ b/README.md
@@ -116,7 +116,7 @@ See [tools/sync_drop_caches.cpp](tools/sync_drop_caches.cpp)
 ```
 
 * `Result sync()`: flush filesystem caches to disk
-* `Result drop_caches(DropCaches_t mode)`: remove file system caches
+* `Result drop_caches(DropCaches_t mode = DropCaches_t(PAGECACHE | ENTRIES))`: remove file system caches
   * `mode = PAGECACHE`: drop page caches
   * `mode = ENTRIES`: drop dentries and inodes
   * `mode = PAGECACHE | ENTRIES`: both
diff --git a/include/perfect/drop_caches.hpp b/include/perfect/drop_caches.hpp
index 84de9cd..27c9782 100644
--- a/include/perfect/drop_caches.hpp
+++ b/include/perfect/drop_caches.hpp
@@ -24,7 +24,7 @@ Result sync() {
     return Result::SUCCESS;
 }
 
-Result drop_caches(const DropCaches_t mode) {
+Result drop_caches(const DropCaches_t mode = DropCaches_t(PAGECACHE | ENTRIES)) {
     using detail::write_str;
     const std::string path = "/proc/sys/vm/drop_caches";
     if (mode & PAGECACHE & ENTRIES) {
diff --git a/tools/perfect.cpp b/tools/perfect.cpp
index fa46d0d..3d224e8 100644
--- a/tools/perfect.cpp
+++ b/tools/perfect.cpp
@@ -15,6 +15,7 @@
 #include "perfect/cpu_turbo.hpp"
 #include "perfect/os_perf.hpp"
 #include "perfect/detail/os/linux.hpp"
+#include "perfect/drop_caches.hpp"
 
 // argv should be null-terminated
 int fork_child(char *const *argv) {
@@ -72,6 +73,7 @@ int main(int argc, char **argv) {
   bool aslr = false;
   bool cpuTurbo = false;
   bool maxOsPerf = true;
+  bool dropCaches = true;
 
   std::vector<std::string> program;
 
@@ -83,6 +85,7 @@ int main(int argc, char **argv) {
 
 
   auto cli = (shieldGroup, 
+              option("--no-drop-cache").set(dropCaches, false).doc("do not drop filesystem caches"),
               option("--no-max-perf").set(maxOsPerf, false).doc("do not max os perf"),
               option("--no-aslr").set(aslr, false).doc("disable ASLR"),
               option("--no-cpu-turbo").set(cpuTurbo, false).doc("disable CPU turbo"),
@@ -167,6 +170,12 @@ int main(int argc, char **argv) {
     } 
   }
 
+  // handle file system caches
+  if (dropCaches) {
+    std::cerr << "clearing file system cache\n";
+    PERFECT(perfect::drop_caches());
+  }
+
   // parent should return
   std::cerr << "exec ";
   for (size_t i = 0; i < args.size() - 1; ++i) {