linux-kernel - tickless/dynticks + cpufreq = tsc unstable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 26 Jan 2008 02:02:46 +0300
From:	Michael Tokarev <mjt@....msk.ru>
To:	Linux-kernel <linux-kernel@...r.kernel.org>
Subject: tickless/dynticks + cpufreq = tsc unstable

Is it normal that once I enable cpufreq on
a tickless system, it spews a warning:

Clocksource tsc unstable (delta = -288201154 ns)

?

It's an old problem, and I was thinking about
differences between x86-64 (it worked there) and
i386 kernels.  But with 2.6.24, x86-64 can run
tickless as well, and once I enable this mode,
and load dynamic cpufreq governor, the above message
gets printed too.

The system is amd x2-64, all kernels since tickless
has been introduced.

I'm not sure if it's really something to worry about --
probably not, as this system has hpet.  But on another
system, Intel-based, where there was no hpet and jiffies
clocksourse gets selected instead, there were some...
issues still (I don't remember offhand which ones, will
check the next week with new kernel).

Thanks!

/mjt
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/