Ingo Molnar wrote:
* Frank Rowand <[EMAIL PROTECTED]> wrote:
I have attached a patch to add realtime support for PowerPC (32 bit
only). [...]
two comments:
- why is us_to_tb needed? It just seems to add alot of unnecessary
clutter to the patch, while it's not used anywhere.
Sorry, the usage of us_to_tb got dropped from the patch when I moved
it from one of my development trees to another. It gets used in
usecs_to_cycles(). The patch to add that is attached below.
Even with the usage of us_to_tb by usecs_to_cycles(), there is a lot
of added clutter for what is accomplished. I considered a nasty hack
to try to derive the proper value from other sources, but adding
us_to_tb seemed a lot easier to understand.
This patch also adds the dreaded #ifdefs, so I suspect it will not be
the correct implementation long term. I'm not sure if Manish's patch
included the ARM implementation of usecs_to_cycles() - it is a third
case in the #ifdef.
Performance instrumentation is also going to need mcount() and
_mcount(), which is currently a work in progress.
- could you submit the drivers/net/ibm_emac/ibm_emac_core.c patch
upstream as well?
Yes, I will do that.
otherwise it looks pretty clean and straightforward.
Ingo
Source: MontaVista Software, Inc.
Signed-off-by: Frank Rowand <[EMAIL PROTECTED]>
Index: linux-2.6.10/kernel/latency.c
===================================================================
--- linux-2.6.10.orig/kernel/latency.c
+++ linux-2.6.10/kernel/latency.c
@@ -192,7 +192,11 @@ static unsigned long notrace cycles_to_u
static cycles_t notrace usecs_to_cycles(unsigned long delta)
{
+#if defined CONFIG_X86
return (cycles_t) delta * (cycles_t) (cpu_khz/1000+1);
+#elif defined(CONFIG_PPC)
+ return delta * us_to_tb;
+#endif
}
#ifdef CONFIG_LATENCY_TRACE
Thanks,
-Frank (off to vacation for a couple days)
--
Frank Rowand <[EMAIL PROTECTED]>
MontaVista Software, Inc
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