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authorTim Bird <tim.bird@sonymobile.com>2014-12-03 10:42:21 -0800
committerShuah Khan <shuahkh@osg.samsung.com>2014-12-03 19:27:47 -0700
commit3ce51050fadd63737c03627293ca2dc4be238891 (patch)
treee5d3824e81854ab42afc3cb47c1524c23be6a6b3
parentselftests/kcmp: Always try to build the test (diff)
downloadwireguard-linux-3ce51050fadd63737c03627293ca2dc4be238891.tar.xz
wireguard-linux-3ce51050fadd63737c03627293ca2dc4be238891.zip
selftest: size: Add size test for Linux kernel
This test shows the amount of memory used by the system. Note that this is dependent on the user-space that is loaded when this program runs. Optimally, this program would be run as the init program itself. The program is optimized for size itself, to avoid conflating its own execution with that of the system software. The code is compiled statically, with no stdlibs. On my x86_64 system, this results in a statically linked binary of less than 5K. Signed-off-by: Tim Bird <tim.bird@sonymobile.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Diffstat (limited to '')
-rw-r--r--tools/testing/selftests/Makefile1
-rw-r--r--tools/testing/selftests/size/.gitignore1
-rw-r--r--tools/testing/selftests/size/Makefile12
-rw-r--r--tools/testing/selftests/size/get_size.c100
4 files changed, 114 insertions, 0 deletions
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 45f145c6f843..fa91aefc8d19 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -15,6 +15,7 @@ TARGETS += user
TARGETS += sysctl
TARGETS += firmware
TARGETS += ftrace
+TARGETS += size
TARGETS_HOTPLUG = cpu-hotplug
TARGETS_HOTPLUG += memory-hotplug
diff --git a/tools/testing/selftests/size/.gitignore b/tools/testing/selftests/size/.gitignore
new file mode 100644
index 000000000000..189b7818de34
--- /dev/null
+++ b/tools/testing/selftests/size/.gitignore
@@ -0,0 +1 @@
+get_size
diff --git a/tools/testing/selftests/size/Makefile b/tools/testing/selftests/size/Makefile
new file mode 100644
index 000000000000..04dc25e4fa92
--- /dev/null
+++ b/tools/testing/selftests/size/Makefile
@@ -0,0 +1,12 @@
+CC = $(CROSS_COMPILE)gcc
+
+all: get_size
+
+get_size: get_size.c
+ $(CC) -static -ffreestanding -nostartfiles -s $< -o $@
+
+run_tests: all
+ ./get_size
+
+clean:
+ $(RM) get_size
diff --git a/tools/testing/selftests/size/get_size.c b/tools/testing/selftests/size/get_size.c
new file mode 100644
index 000000000000..2d1af7cca463
--- /dev/null
+++ b/tools/testing/selftests/size/get_size.c
@@ -0,0 +1,100 @@
+/*
+ * Copyright 2014 Sony Mobile Communications Inc.
+ *
+ * Licensed under the terms of the GNU GPL License version 2
+ *
+ * Selftest for runtime system size
+ *
+ * Prints the amount of RAM that the currently running system is using.
+ *
+ * This program tries to be as small as possible itself, to
+ * avoid perturbing the system memory utilization with its
+ * own execution. It also attempts to have as few dependencies
+ * on kernel features as possible.
+ *
+ * It should be statically linked, with startup libs avoided.
+ * It uses no library calls, and only the following 3 syscalls:
+ * sysinfo(), write(), and _exit()
+ *
+ * For output, it avoids printf (which in some C libraries
+ * has large external dependencies) by implementing it's own
+ * number output and print routines, and using __builtin_strlen()
+ */
+
+#include <sys/sysinfo.h>
+#include <unistd.h>
+
+#define STDOUT_FILENO 1
+
+static int print(const char *s)
+{
+ return write(STDOUT_FILENO, s, __builtin_strlen(s));
+}
+
+static inline char *num_to_str(unsigned long num, char *buf, int len)
+{
+ unsigned int digit;
+
+ /* put digits in buffer from back to front */
+ buf += len - 1;
+ *buf = 0;
+ do {
+ digit = num % 10;
+ *(--buf) = digit + '0';
+ num /= 10;
+ } while (num > 0);
+
+ return buf;
+}
+
+static int print_num(unsigned long num)
+{
+ char num_buf[30];
+
+ return print(num_to_str(num, num_buf, sizeof(num_buf)));
+}
+
+static int print_k_value(const char *s, unsigned long num, unsigned long units)
+{
+ unsigned long long temp;
+ int ccode;
+
+ print(s);
+
+ temp = num;
+ temp = (temp * units)/1024;
+ num = temp;
+ ccode = print_num(num);
+ print("\n");
+ return ccode;
+}
+
+/* this program has no main(), as startup libraries are not used */
+void _start(void)
+{
+ int ccode;
+ struct sysinfo info;
+ unsigned long used;
+
+ print("Testing system size.\n");
+ print("1..1\n");
+
+ ccode = sysinfo(&info);
+ if (ccode < 0) {
+ print("not ok 1 get runtime memory use\n");
+ print("# could not get sysinfo\n");
+ _exit(ccode);
+ }
+ /* ignore cache complexities for now */
+ used = info.totalram - info.freeram - info.bufferram;
+ print_k_value("ok 1 get runtime memory use # size = ", used,
+ info.mem_unit);
+
+ print("# System runtime memory report (units in Kilobytes):\n");
+ print_k_value("# Total: ", info.totalram, info.mem_unit);
+ print_k_value("# Free: ", info.freeram, info.mem_unit);
+ print_k_value("# Buffer: ", info.bufferram, info.mem_unit);
+ print_k_value("# In use: ", used, info.mem_unit);
+
+ _exit(0);
+}