Hello, I wrote:
> In addition to clock wrap check being falsely triggered with 32-bit cycles_t,
> as noticed to Kevin Hilman, there's another issue: using %Lx format to print
> 32-bit values warrants erroneous values on 32-bit machines like ARM and PPC32.
> Signed-off-by: Sergei Shtylyov <[EMAIL PROTECTED]>
> ---
> PPC32 actually has 64-bit timebase counter, so could provide for 64-bit
> cycles_t -- maybe it's worth to rewrite get_cycles() to read both lower and
> upper registers?
This one (called latency-tracer-prink-fix.patch in the broken out
patchset) has been erroneously "restored" some months ago. Since
preempt_max_latency is of type 'unsigned long' now and all the other vars are
of type 'cycle_t' (which aliases 'u64'), only the first cast is actually
needed (or rather, the first format specifier needs to be changed to %08lx).
Erm, maybe I'll cook a patch...
> Index: linux-2.6/kernel/latency_trace.c
> ===================================================================
> --- linux-2.6.orig/kernel/latency_trace.c
> +++ linux-2.6/kernel/latency_trace.c
> @@ -1623,8 +1623,8 @@ check_critical_timing(int cpu, struct cp
> #ifndef CONFIG_CRITICAL_LATENCY_HIST
> if (!preempt_thresh && preempt_max_latency > delta) {
> printk("bug: updating %016Lx > %016Lx?\n",
> - preempt_max_latency, delta);
> - printk(" [%016Lx %016Lx %016Lx]\n", T0, T1, T2);
> + (u64)preempt_max_latency, (u64)delta);
> + printk(" [%016Lx %016Lx %016Lx]\n", (u64)T0, (u64)T1, (u64)T2);
> }
> #endif
WBR, Sergei
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