diff --git a/Makefile b/Makefile
index d970cd00e9..b2653ee64f 100644
--- a/Makefile
+++ b/Makefile
@@ -638,6 +638,7 @@ TEST_PROGRAMS_NEED_X += test-ctype
 TEST_PROGRAMS_NEED_X += test-config
 TEST_PROGRAMS_NEED_X += test-date
 TEST_PROGRAMS_NEED_X += test-delta
+TEST_PROGRAMS_NEED_X += test-drop-caches
 TEST_PROGRAMS_NEED_X += test-dump-cache-tree
 TEST_PROGRAMS_NEED_X += test-dump-fsmonitor
 TEST_PROGRAMS_NEED_X += test-dump-split-index
diff --git a/t/helper/.gitignore b/t/helper/.gitignore
index f97400b8cc..87a648a7cf 100644
--- a/t/helper/.gitignore
+++ b/t/helper/.gitignore
@@ -3,6 +3,7 @@
 /test-config
 /test-date
 /test-delta
+/test-drop-caches
 /test-dump-cache-tree
 /test-dump-fsmonitor
 /test-dump-split-index
diff --git a/t/helper/test-drop-caches.c b/t/helper/test-drop-caches.c
new file mode 100644
index 0000000000..bd1a857d52
--- /dev/null
+++ b/t/helper/test-drop-caches.c
@@ -0,0 +1,164 @@
+#include "git-compat-util.h"
+
+#if defined(GIT_WINDOWS_NATIVE)
+
+static int cmd_sync(void)
+{
+	char Buffer[MAX_PATH];
+	DWORD dwRet;
+	char szVolumeAccessPath[] = "\\\\.\\X:";
+	HANDLE hVolWrite;
+	int success = 0;
+
+	dwRet = GetCurrentDirectory(MAX_PATH, Buffer);
+	if ((0 == dwRet) || (dwRet > MAX_PATH))
+		return error("Error getting current directory");
+
+	if ((Buffer[0] < 'A') || (Buffer[0] > 'Z'))
+		return error("Invalid drive letter '%c'", Buffer[0]);
+
+	szVolumeAccessPath[4] = Buffer[0];
+	hVolWrite = CreateFile(szVolumeAccessPath, GENERIC_READ | GENERIC_WRITE,
+		FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
+	if (INVALID_HANDLE_VALUE == hVolWrite)
+		return error("Unable to open volume for writing, need admin access");
+
+	success = FlushFileBuffers(hVolWrite);
+	if (!success)
+		error("Unable to flush volume");
+
+	CloseHandle(hVolWrite);
+
+	return !success;
+}
+
+#define STATUS_SUCCESS			(0x00000000L)
+#define STATUS_PRIVILEGE_NOT_HELD	(0xC0000061L)
+
+typedef enum _SYSTEM_INFORMATION_CLASS {
+	SystemMemoryListInformation = 80,
+} SYSTEM_INFORMATION_CLASS;
+
+typedef enum _SYSTEM_MEMORY_LIST_COMMAND {
+	MemoryCaptureAccessedBits,
+	MemoryCaptureAndResetAccessedBits,
+	MemoryEmptyWorkingSets,
+	MemoryFlushModifiedList,
+	MemoryPurgeStandbyList,
+	MemoryPurgeLowPriorityStandbyList,
+	MemoryCommandMax
+} SYSTEM_MEMORY_LIST_COMMAND;
+
+static BOOL GetPrivilege(HANDLE TokenHandle, LPCSTR lpName, int flags)
+{
+	BOOL bResult;
+	DWORD dwBufferLength;
+	LUID luid;
+	TOKEN_PRIVILEGES tpPreviousState;
+	TOKEN_PRIVILEGES tpNewState;
+
+	dwBufferLength = 16;
+	bResult = LookupPrivilegeValueA(0, lpName, &luid);
+	if (bResult) {
+		tpNewState.PrivilegeCount = 1;
+		tpNewState.Privileges[0].Luid = luid;
+		tpNewState.Privileges[0].Attributes = 0;
+		bResult = AdjustTokenPrivileges(TokenHandle, 0, &tpNewState,
+			(DWORD)((LPBYTE)&(tpNewState.Privileges[1]) - (LPBYTE)&tpNewState),
+			&tpPreviousState, &dwBufferLength);
+		if (bResult) {
+			tpPreviousState.PrivilegeCount = 1;
+			tpPreviousState.Privileges[0].Luid = luid;
+			tpPreviousState.Privileges[0].Attributes = flags != 0 ? 2 : 0;
+			bResult = AdjustTokenPrivileges(TokenHandle, 0, &tpPreviousState,
+				dwBufferLength, 0, 0);
+		}
+	}
+	return bResult;
+}
+
+static int cmd_dropcaches(void)
+{
+	HANDLE hProcess = GetCurrentProcess();
+	HANDLE hToken;
+	HMODULE ntdll;
+	DWORD(WINAPI *NtSetSystemInformation)(INT, PVOID, ULONG);
+	SYSTEM_MEMORY_LIST_COMMAND command;
+	int status;
+
+	if (!OpenProcessToken(hProcess, TOKEN_QUERY | TOKEN_ADJUST_PRIVILEGES, &hToken))
+		return error("Can't open current process token");
+
+	if (!GetPrivilege(hToken, "SeProfileSingleProcessPrivilege", 1))
+		return error("Can't get SeProfileSingleProcessPrivilege");
+
+	CloseHandle(hToken);
+
+	ntdll = LoadLibrary("ntdll.dll");
+	if (!ntdll)
+		return error("Can't load ntdll.dll, wrong Windows version?");
+
+	NtSetSystemInformation =
+		(DWORD(WINAPI *)(INT, PVOID, ULONG))GetProcAddress(ntdll, "NtSetSystemInformation");
+	if (!NtSetSystemInformation)
+		return error("Can't get function addresses, wrong Windows version?");
+
+	command = MemoryPurgeStandbyList;
+	status = NtSetSystemInformation(
+		SystemMemoryListInformation,
+		&command,
+		sizeof(SYSTEM_MEMORY_LIST_COMMAND)
+	);
+	if (status == STATUS_PRIVILEGE_NOT_HELD)
+		error("Insufficient privileges to purge the standby list, need admin access");
+	else if (status != STATUS_SUCCESS)
+		error("Unable to execute the memory list command %d", status);
+
+	FreeLibrary(ntdll);
+
+	return status;
+}
+
+#elif defined(__linux__)
+
+static int cmd_sync(void)
+{
+	return system("sync");
+}
+
+static int cmd_dropcaches(void)
+{
+	return system("echo 3 | sudo tee /proc/sys/vm/drop_caches");
+}
+
+#elif defined(__APPLE__)
+
+static int cmd_sync(void)
+{
+	return system("sync");
+}
+
+static int cmd_dropcaches(void)
+{
+	return system("sudo purge");
+}
+
+#else
+
+static int cmd_sync(void)
+{
+	return 0;
+}
+
+static int cmd_dropcaches(void)
+{
+	return error("drop caches not implemented on this platform");
+}
+
+#endif
+
+int cmd_main(int argc, const char **argv)
+{
+	cmd_sync();
+	return cmd_dropcaches();
+}
diff --git a/t/perf/p7519-fsmonitor.sh b/t/perf/p7519-fsmonitor.sh
new file mode 100755
index 0000000000..16d1bf72e5
--- /dev/null
+++ b/t/perf/p7519-fsmonitor.sh
@@ -0,0 +1,184 @@
+#!/bin/sh
+
+test_description="Test core.fsmonitor"
+
+. ./perf-lib.sh
+
+#
+# Performance test for the fsmonitor feature which enables git to talk to a
+# file system change monitor and avoid having to scan the working directory
+# for new or modified files.
+#
+# By default, the performance test will utilize the Watchman file system
+# monitor if it is installed.  If Watchman is not installed, it will use a
+# dummy integration script that does not report any new or modified files.
+# The dummy script has very little overhead which provides optimistic results.
+#
+# The performance test will also use the untracked cache feature if it is
+# available as fsmonitor uses it to speed up scanning for untracked files.
+#
+# There are 3 environment variables that can be used to alter the default
+# behavior of the performance test:
+#
+# GIT_PERF_7519_UNTRACKED_CACHE: used to configure core.untrackedCache
+# GIT_PERF_7519_SPLIT_INDEX: used to configure core.splitIndex
+# GIT_PERF_7519_FSMONITOR: used to configure core.fsMonitor
+#
+# The big win for using fsmonitor is the elimination of the need to scan the
+# working directory looking for changed and untracked files. If the file
+# information is all cached in RAM, the benefits are reduced.
+#
+# GIT_PERF_7519_DROP_CACHE: if set, the OS caches are dropped between tests
+#
+
+test_perf_large_repo
+test_checkout_worktree
+
+test_lazy_prereq UNTRACKED_CACHE '
+	{ git update-index --test-untracked-cache; ret=$?; } &&
+	test $ret -ne 1
+'
+
+test_lazy_prereq WATCHMAN '
+	{ command -v watchman >/dev/null 2>&1; ret=$?; } &&
+	test $ret -ne 1
+'
+
+if test_have_prereq WATCHMAN
+then
+	# Convert unix style paths to escaped Windows style paths for Watchman
+	case "$(uname -s)" in
+	MSYS_NT*)
+	  GIT_WORK_TREE="$(cygpath -aw "$PWD" | sed 's,\\,/,g')"
+	  ;;
+	*)
+	  GIT_WORK_TREE="$PWD"
+	  ;;
+	esac
+fi
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"
+then
+	# When using GIT_PERF_7519_DROP_CACHE, GIT_PERF_REPEAT_COUNT must be 1 to
+	# generate valid results. Otherwise the caching that happens for the nth
+	# run will negate the validity of the comparisons.
+	if test "$GIT_PERF_REPEAT_COUNT" -ne 1
+	then
+		echo "warning: Setting GIT_PERF_REPEAT_COUNT=1" >&2
+		GIT_PERF_REPEAT_COUNT=1
+	fi
+fi
+
+test_expect_success "setup for fsmonitor" '
+	# set untrackedCache depending on the environment
+	if test -n "$GIT_PERF_7519_UNTRACKED_CACHE"
+	then
+		git config core.untrackedCache "$GIT_PERF_7519_UNTRACKED_CACHE"
+	else
+		if test_have_prereq UNTRACKED_CACHE
+		then
+			git config core.untrackedCache true
+		else
+			git config core.untrackedCache false
+		fi
+	fi &&
+
+	# set core.splitindex depending on the environment
+	if test -n "$GIT_PERF_7519_SPLIT_INDEX"
+	then
+		git config core.splitIndex "$GIT_PERF_7519_SPLIT_INDEX"
+	fi &&
+
+	# set INTEGRATION_SCRIPT depending on the environment
+	if test -n "$GIT_PERF_7519_FSMONITOR"
+	then
+		INTEGRATION_SCRIPT="$GIT_PERF_7519_FSMONITOR"
+	else
+		#
+		# Choose integration script based on existence of Watchman.
+		# If Watchman exists, watch the work tree and attempt a query.
+		# If everything succeeds, use Watchman integration script,
+		# else fall back to an empty integration script.
+		#
+		mkdir .git/hooks &&
+		if test_have_prereq WATCHMAN
+		then
+			INTEGRATION_SCRIPT=".git/hooks/fsmonitor-watchman" &&
+			cp "$TEST_DIRECTORY/../templates/hooks--fsmonitor-watchman.sample" "$INTEGRATION_SCRIPT" &&
+			watchman watch "$GIT_WORK_TREE" &&
+			watchman watch-list | grep -q -F "$GIT_WORK_TREE"
+		else
+			INTEGRATION_SCRIPT=".git/hooks/fsmonitor-empty" &&
+			write_script "$INTEGRATION_SCRIPT"<<-\EOF
+			EOF
+		fi
+	fi &&
+
+	git config core.fsmonitor "$INTEGRATION_SCRIPT" &&
+	git update-index --fsmonitor
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status -uno (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uno
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status -uall (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uall
+'
+
+test_expect_success "setup without fsmonitor" '
+	unset INTEGRATION_SCRIPT &&
+	git config --unset core.fsmonitor &&
+	git update-index --no-fsmonitor
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status -uno (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uno
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-drop-caches
+fi
+
+test_perf "status -uall (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git status -uall
+'
+
+if test_have_prereq WATCHMAN
+then
+	watchman watch-del "$GIT_WORK_TREE" >/dev/null 2>&1 &&
+
+	# Work around Watchman bug on Windows where it holds on to handles
+	# preventing the removal of the trash directory
+	watchman shutdown-server >/dev/null 2>&1
+fi
+
+test_done