init: Use android::base::boot_clock instead of /proc/uptime
/proc/uptime internally uses whatever would be returned by
clock_gettime(CLOCK_BOOTTIME), so use android::base::boot_clock instead
which avoids parsing strings and rounding errors.
Bug: 77273909
Test: CtsBootStatsTestCases
Change-Id: Ic162eefcf226073949a18cca55db3c2324b98749
diff --git a/init/bootchart.cpp b/init/bootchart.cpp
index 379b4fa..c2cf573 100644
--- a/init/bootchart.cpp
+++ b/init/bootchart.cpp
@@ -32,12 +32,14 @@
#include <mutex>
#include <thread>
+#include <android-base/chrono_utils.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
using android::base::StringPrintf;
+using android::base::boot_clock;
using namespace std::chrono_literals;
namespace android {
@@ -50,9 +52,9 @@
static bool g_bootcharting_finished;
static long long get_uptime_jiffies() {
- std::string uptime;
- if (!android::base::ReadFileToString("/proc/uptime", &uptime)) return 0;
- return 100LL * strtod(uptime.c_str(), NULL);
+ constexpr int64_t kNanosecondsPerJiffy = 10000000;
+ boot_clock::time_point uptime = boot_clock::now();
+ return uptime.time_since_epoch().count() / kNanosecondsPerJiffy;
}
static std::unique_ptr<FILE, decltype(&fclose)> fopen_unique(const char* filename,