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  1. Mar 06, 2012
    • Jens Rottmann's avatar
      cs5535-clockevt: Don't ignore MFGPT on SMP-capable kernels · fc579da7
      Jens Rottmann authored 
      

On SMP-capable kernels (e.g.  generic distro kernel) the cs5535-clockevt
driver loads but is not actually used.

Setting cpumask to cpu_all_mask works for UP-only kernels, but if compiled
for SMP - though still running on the same UP hardware -
kernel/time/tick-common.c:tick_check_new_device() reads this as
"non-cpu-local" and silently ignores the device.

If we leave cpumask unset clockevents_register_device() will initialize it
and the cs5535-clockevt driver will be used no matter how the kernel was
compiled.  Should anyone ever manage to stick a CS553x in an SMP system
(is this even possible?) then a warning will be printed.  This is fine as
the cs5535-clockevt driver was never written/tested for SMP.

If bisecting led you here this patch may have exposed a pre-existing MFGPT
problem.  Configure for UP-only and re-check.

Signed-off-by: default avatarJens Rottmann <JRottmann@LiPPERTEmbedded.de>
Acked-by: default avatarAndres Salomon <dilinger@queued.net>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      fc579da7
  3. Feb 27, 2012
  5. Feb 22, 2012
    • Ingo Molnar's avatar
      clocksource: scx200_hrt: Fix the build · 10ea9d6f
      Ingo Molnar authored 
      This commit:

  12d6d412: clocksource: scx200_hrt: Convert scx200 to use clocksource_register_hz

Breaks the build on x86-32:

  drivers/clocksource/scx200_hrt.c: In function ‘init_hrt_clocksource’:
  drivers/clocksource/scx200_hrt.c:95:0: error: unterminated argument list invoking macro "pr_info"
  drivers/clocksource/scx200_hrt.c:84:2: error: ‘pr_info’ undeclared (first use in this function)

It could not possibly have been build tested, because it had this mismerge:

	pr_info("enabling scx200 high-res timer (%s MHz +%d ppm)\n",
	printk(KERN_INFO "enabling scx200 high-res timer (%s MHz +%d ppm)\n",
		mhz27 ? "27":"1", ppm);

Cc: Jim Cromie <jim.cromie@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/n/tip-jceb26fns5w7tv8edlivhxpa@git.kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      10ea9d6f
    • Suresh Siddha's avatar
      x86/tsc: Reduce the TSC sync check time for core-siblings · b0e5c779
      Suresh Siddha authored 
      

For each logical CPU that is coming online, we spend 20msec for
checking the TSC synchronization. And as this is done
sequentially for each logical CPU boot, this time gets added up
depending on the number of logical CPU's supported by the
platform.

Minimize this by using the socket topology information.

If the target CPU coming online doesn't have any of its
core-siblings online, a timeout of 20msec will be used for the
TSC-warp measurement loop. Otherwise a smaller timeout of 2msec
will be used, as we have some information about this socket
already (and this information grows as we have more and more
logical-siblings in that socket).

Ideally we should be able to skip the TSC sync check on the
other core-siblings, if the first logical CPU in a socket passed
the sync test. But as the TSC is per-logical CPU and can
potentially be modified wrongly by the bios before the OS boot,
TSC sync test for smaller duration should be able to catch such
errors. Also this will catch the condition where all the cores
in the socket doesn't get reset at the same time.

For example, with this modification, time spent in TSC sync
checks on a 4 socket 10-core with HT system gets reduced from
1580msec to 212msec.

Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Acked-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jack Steiner <steiner@sgi.com>
Cc: venki@google.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1328581940.29790.20.camel@sbsiddha-desk.sc.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      b0e5c779
  7. Feb 16, 2012
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