Re: [PATCH 10/17] 2.6.17.1 perfmon2 patch for review: PMU context switch

[Chuck Ebbert]

In-Reply-To: <20060630204032.GB22835@xxxxxxxxxxxxxxxxx>

On Fri, 30 Jun 2006 13:40:32 -0700, Stephane Eranian wrote:

> As Andi is suggesting, I think this may depends on how the BIOS implements
> the low-power state. I have tried the same command on my dual Opteron 250
> 2.4GHz and I get:
> $ pfmon --us-c -ecpu_clk_unhalted,interrupts_masked_cycles -k --system-wide -t 10
> <session to end in 10 seconds>
> CPU0                     9,520,303 CPU_CLK_UNHALTED
> CPU0                     3,726,315 INTERRUPTS_MASKED_CYCLES
> CPU1                    21,268,151 CPU_CLK_UNHALTED
> CPU1                    14,515,389 INTERRUPTS_MASKED_CYCLES

That is similar to what I get with idle=halt. Are you not using ACPI
for idle?

Try this:

$ pfmon -ecpu_clk_unhalted,interrupts_masked_cycles_with_interrupt_pending,interrupts_masked_cycles,cycles_no_fpu_ops_retired -k --system-wide -t 10
<session to end in 10 seconds>
CPU0     95016828 CPU_CLK_UNHALTED
CPU0     36472783 INTERRUPTS_MASKED_CYCLES_WITH_INTERRUPT_PENDING
CPU0     67484408 INTERRUPTS_MASKED_CYCLES
CPU0    445326968 CYCLES_NO_FPU_OPS_RETIRED

That's what I get with idle=halt.  Since the kernel doesn't do FP
the last line should equal clock cycles.  If it were running at full
speed it would be 16 billion...

-- 
Chuck
 "You can't read a newspaper if you can't read."  --George W. Bush
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/