Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 16 Jan 2003 12:18:37 -0800 | From | Andrew Morton <> | Subject | Re: [patch] Make prof_counter use per-cpu areas patch 1/4 -- x86 arch |
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Ravikiran G Thirumalai <kiran@in.ibm.com> wrote: > > Even cpu_possible does not seem to be setup this early. Seems like > reinitialisation of prof_counter/prof_multiplier et al is redundant. > Here's a newer patch which removes this initialisation at smp_boot_cpus. > Works fine for me (tested same on a 4 way with difft profiling multipliers.. > LOC interrupts seem to fire at the right intervals).
Things still look a bit fishy to me.
In apic.c:
int prof_multiplier[NR_CPUS] = { 1, }; int prof_old_multiplier[NR_CPUS] = { 1, }; DEFINE_PER_CPU(int, prof_counter) = 1;
This means that all the prof_counter values are set to 1, but the multiplier arrays have 1 in the zeroeth entry, and zero in the remaining entries.
The zero multipliers remain in place until someone runs setup_profiling_timer().
One approach would be to initialise all members:
int prof_multiplier[NR_CPUS] = { [ 0 ... NR_CPUS-1 ] = 1 };
But I think it would be better to put the multipliers into per-cpu memory as well. Something like:
struct profiling_info { int multiplier; int old_multiplier; int counter; };
DEFINE_PER_CPU(struct profiling_info, profiling_info) = {1, 1, 1};
Perhaps?
Also bits and pieces of the profiling code seem to be randomly splattered all over the place. Consolidating it all into the one .c file would be nice.
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