> OK, so I resurrected x86_64-mm-sched-clock-share.patch and > x86_64-mm-sched-clock64.patch. The x86_64 box hangs on boot when using > netconsole and printk timestamps too. Removing "time" from the kernel boot > command line prevents that.
Ah. But ktime_get shouldn't printk. Or did you change that? > > This explains why the hang only happens with > x86_64-mm-log-reason-why-tsc-was-marked-unstable.patch applied, too: that > patch must be triggering a printk inside xtime_lock. > > Does someone want to cook up a lockless printk_clock() for i386 and x86_64? Just use jiffies directly in printk. That's only HZ accurate, but should be good enough for printk. One could use pure monotonic xtime as fallback instead of ktime_get in sched_clock. The trouble is just that they might cause sched_clock to go backwards during a temporary instability period (cpufreq change) because the xtime will be always a bit behind the TSC and a TSC->xtime conversion will lose time. At least the scheduler doesn't handle backwards time warp on a CPU gratefully. Ok I guess it could return max(last_value_before_instability, xtime) -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
