Comment 5 for bug 647472

This is no specific issue of procps, it just returns the value from the kernel. The kernel documents (in the source) that the value includes the time spent in suspend.

/proc/uptime gets the value from here:

https://elixir.bootlin.com/linux/v4.20.3/source/include/linux/timekeeping.h#L93

/**
 * ktime_get_boottime - Returns monotonic time since boot in ktime_t format
 *
 * This is similar to CLOCK_MONTONIC/ktime_get, but also includes the
 * time spent in suspend.
 */
static inline ktime_t ktime_get_boottime(void)
{
 return ktime_get_with_offset(TK_OFFS_BOOT);
}