ACPI: handle timer ticks proactively
Subsystems (2)
RFC PATCH 2/2 ACPI: handle timer ticks proactively
Hi All,
This patch takes advantage of the infrastructure introduced in the last patch, and allows the processor idle algorithm to proactively choose a c-state based on the time the next timer interrupt is expected to occur. It preserves the residency metric, so the algorithm should, in theory, remain effective against bursts of activity from other interrupt sources.
This patch is mostly intended to be illustrative. There may be some "#ifdef CONFIG_ACPI" issues, and I would appreciate any advice on implementing this more cleanly.
Cheers,
Adam
Patch is against 2.6.18-rc4.
Signed-off-by Adam Belay <[email protected]>
--- drivers/acpi/processor_idle.c | 17 +++++++++++++++++ include/acpi/processor.h | 2 ++ kernel/timer.c | 7 +++++++ 3 files changed, 26 insertions(+)
drivers/acpi/processor_idle.c +17 -0
@@ -64,6 +64,7 @@* Currently, we aim for the entry/exit latency to be 20% of measured residency. */ #define RESIDENCY_TO_LATENCY_RATIO 5 +#define TIMER_TICKS (PM_TIMER_FREQUENCY / HZ)/* -------------------------------------------------------------------------- Power Management
@@ -271,6 +272,22 @@int count =min (pr->power.count, (int ) max_cstate); cx = &pr->power.states[state_idx]; +/* +* We are proactive with timer interrupts. After a timer +* interrupt has occurred the previous sleep_ticks value is +* restored. +*/ +if (pr->power.pretimer_last_ticks) { + sleep_ticks = pr->power.pretimer_last_ticks; + pr->power.pretimer_last_ticks =0 ; + } + t1 =inl (acpi_fadt.xpm_tmr_blk.address); + i =TIMER_TICKS - t1 + pr->power.timer_tick; +if (i < sleep_ticks) { + pr->power.pretimer_last_ticks = sleep_ticks; + sleep_ticks = i; + } +if (cx->target_ticks < sleep_ticks) {/* promotion */ for (i = state_idx +1 ; i <= count; i++) { cx = &pr->power.states[i];
kernel/timer.c +7 -0
@@ -41,6 +41,9 @@#include <asm/timex.h> #include <asm/io.h> +#include <acpi/acpi_bus.h> +#include <acpi/processor.h> +#ifdef CONFIG_TIME_INTERPOLATION static void time_interpolator_update (long delta_nsec);#else
@@ -1175,6 +1178,10 @@ {struct task_struct *p = current;int cpu =smp_processor_id (); +struct acpi_processor *pr = processors[cpu]; + +if (pr) + pr->power.timer_tick =inl (acpi_fadt.xpm_tmr_blk.address);/* Note: this timer irq context must be accounted for as well. */ if (user_tick)
include/acpi/processor.h +2 -0
@@ -60,6 +60,8 @@u32 bm_activity;u32 bm_veto_state;u32 last_ticks; +u32 timer_tick; +u32 pretimer_last_ticks;int count;struct acpi_processor_cx states[ACPI_PROCESSOR_MAX_POWER ]; };
I ran bltk this patch vs 2.6.18.1 on a Dell i6400 Core Duo laptop. Initial result (1 measurement of each kernel) is that
battery life is unchanged, but response time improves with the new patch.
Summary files attached.
thanks,
-Len
Workload
Workload : Open Office (office) 1.0.4
System
Manufacturer : Dell Inc.
Product Name : MM061
System Release : SUSE LINUX 10.1 (i586)
Kernel Release : 2.6.18.1-dirty
CPU
CPU : 0
CPU Model : Genuine Intel(R) CPU T2500 @ 2.00GHz
Cache Size : 2048 KB
Num Logical : 2
Governor : ondemand
Timer : 0.00
Interrupts : 8.93
Load : 1.58%
Max Frequecy : 2000000
Min Frequency : 1000000
Average Frequency : 1017733
Bus Master Activity : 0.00
C1 : 31.88
C2 : 32.65
C3 : 260.95
P0 : 1.69
P1 : 0.09
P2 : 0.05
P3 : 98.16
CPU
CPU : 1
CPU Model : Genuine Intel(R) CPU T2500 @ 2.00GHz
Cache Size : 2048 KB
Num Logical : 2
Governor : ondemand
Timer : 249.98
Interrupts : 2.82
Load : 1.92%
Max Frequecy : 2000000
Min Frequency : 1000000
Average Frequency : 1017733
Bus Master Activity : 0.00
C1 : 4.19
C2 : 5.03
C3 : 287.82
P0 : 1.69
P1 : 0.09
P2 : 0.05
P3 : 98.16
Memory
Memory Size : 2064260 kB
Swap Size : 2104472 kB
Max Memory : 664196 kB
Max Swap : 0 kB
Display
Grafic Model : Intel Corporation Mobile 945GM/GMS/940GML Express Integrated Graphics Controller (rev 03)
Display Size : 1280x800x16
Display State : on 100.00%, standby 0.00%, suspend 0.00%, off 0.00%
HD
HD Model : HTS721010G9SA00
HD Size : 100030 MBytes (100 GB)
HD RPM : -
HD Reads : 0.00 per sec
HD Writes : 2.77 per sec
HD State : active/idle 0.00%, standby 100.00%, sleeping 0.00%
BAT
Battery Model : DELLUD2646
Charging State : charged
Design Voltage : 11100 mV
Design Capacity : 53280 mWh (100.00%)
Last Full Capacity : 48384 mWh (90.81%)
Remaining Capacity : 53280 mWh (100.00%)
Start Capacity : 53280 mWh (100.00%)
Finish Capacity : 11 mWh (0.02%)
Drain Rate : 16.31 W (4.53 mWh per sec)
Design Battery Rating : 196 min (03:16:02)
Rating
Battery Rating : 196 min (03:16:00)
Iterations : 16.33
Cycle Time : 720.00 sec
Work Time : 481.48 sec
Response Time : 8.28 sec
Score : 289.92
Source
Source : results.office.amb2a
Comment
Comment : -
Test Result
Result : Passed
Workload
Workload : Open Office (office) 1.0.4
System
Manufacturer : Dell Inc.
Product Name : MM061
System Release : SUSE LINUX 10.1 (i586)
Kernel Release : 2.6.18.1
CPU
CPU : 0
CPU Model : Genuine Intel(R) CPU T2500 @ 2.00GHz
Cache Size : 2048 KB
Num Logical : 2
Governor : ondemand
Timer : 0.00
Interrupts : 11.84
Load : 2.18%
Max Frequecy : 2000000
Min Frequency : 1000000
Average Frequency : 1016988
Bus Master Activity : 0.00
C1 : 0.00
C2 : 10.39
C3 : 565.52
P0 : 1.63
P1 : 0.09
P2 : 0.03
P3 : 98.25
CPU
CPU : 1
CPU Model : Genuine Intel(R) CPU T2500 @ 2.00GHz
Cache Size : 2048 KB
Num Logical : 2
Governor : ondemand
Timer : 249.98
Interrupts : 0.00
Load : 1.43%
Max Frequecy : 2000000
Min Frequency : 1000000
Average Frequency : 1016988
Bus Master Activity : 0.00
C1 : 0.00
C2 : 11.11
C3 : 323.20
P0 : 1.63
P1 : 0.09
P2 : 0.03
P3 : 98.25
Memory
Memory Size : 2064260 kB
Swap Size : 2104472 kB
Max Memory : 658288 kB
Max Swap : 0 kB
Display
Grafic Model : Intel Corporation Mobile 945GM/GMS/940GML Express Integrated Graphics Controller (rev 03)
Display Size : 1280x800x16
Display State : on 100.00%, standby 0.00%, suspend 0.00%, off 0.00%
HD
HD Model : HTS721010G9SA00
HD Size : 100030 MBytes (100 GB)
HD RPM : -
HD Reads : 0.07 per sec
HD Writes : 2.76 per sec
HD State : active/idle 0.00%, standby 100.00%, sleeping 0.00%
BAT
Battery Model : DELLUD2646
Charging State : charged
Design Voltage : 11100 mV
Design Capacity : 53280 mWh (100.00%)
Last Full Capacity : 48362 mWh (90.77%)
Remaining Capacity : 53280 mWh (100.00%)
Start Capacity : 53280 mWh (100.00%)
Finish Capacity : 55 mWh (0.10%)
Drain Rate : 16.29 W (4.53 mWh per sec)
Design Battery Rating : 196 min (03:16:12)
Rating
Battery Rating : 196 min (03:16:00)
Iterations : 16.33
Cycle Time : 720.00 sec
Work Time : 482.11 sec
Response Time : 8.87 sec
Score : 270.59
Source
Source : results.office.ref
Comment
Comment : -
Test Result
Result : Passed