RE: [PATCH] OMAP CPUIDLE: CPU Idle latency measurement

27 Aug 2010

...
-----Original Message-----
From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-
owner@vger.kernel.org] On Behalf Of C V, Silesh
Sent: Friday, August 27, 2010 3:28 PM
To: vishwanath.sripathy@linaro.org
Cc: linux-omap@vger.kernel.org; linaro-dev@lists.linaro.org
Subject: Re: [PATCH] OMAP CPUIDLE: CPU Idle latency measurement
g 28, 2010 at 3:38 AM,  vishwanath.sripathy@linaro.org wrote:
...
From: Vishwanath BS vishwanath.sripathy@linaro.org
This patch has instrumentation code for measuring latencies for
various CPUIdle C states for OMAP. Idea here is to capture the
timestamp at various phases of CPU Idle and then compute the sw
latency for various c states. For OMAP, 32k clock is chosen as
reference clock this as is an always on clock. wkup domain memory
(scratchpad memory) is used for storing timestamps. One can see the
worstcase latencies in below sysfs entries (after enabling CONFIG_CPU_IDLE_PROF
in .config). This information can be used to correctly configure cpu idle
latencies for various C states after adding HW latencies for each of
these sw latencies.
/sys/devices/system/cpu/cpu0/cpuidle/state<n>/actual_latency
/sys/devices/system/cpu/cpu0/cpuidle/state<n>/sleep_latency
/sys/devices/system/cpu/cpu0/cpuidle/state<n>/wkup_latency
THis patch is tested on OMAP ZOOM3 using kevin's pm branch.
Signed-off-by: Vishwanath BS vishwanath.sripathy@linaro.org
Cc: linaro-dev@lists.linaro.org

arch/arm/mach-omap2/cpuidle34xx.c |   58 ++++++++++++++++--
 arch/arm/mach-omap2/pm.h          |    5 ++
 arch/arm/mach-omap2/sleep34xx.S   |  121
+++++++++++++++++++++++++++++++++++++
...
drivers/cpuidle/Kconfig           |    5 ++
 drivers/cpuidle/sysfs.c           |   16 +++++-
 include/linux/cpuidle.h           |    3 +
 6 files changed, 202 insertions(+), 6 deletions(-)

diff --git a/arch/arm/mach-omap2/cpuidle34xx.c b/arch/arm/mach-
omap2/cpuidle34xx.c
...
index 3d3d035..398bef8
--- a/arch/arm/mach-omap2/cpuidle34xx.c
+++ b/arch/arm/mach-omap2/cpuidle34xx.c
@@ -25,6 +25,7 @@
 #include <linux/sched.h>
 #include <linux/cpuidle.h>
+#include <linux/clk.h>
 #include <plat/prcm.h>
 #include <plat/irqs.h>
 #include <plat/powerdomain.h>
@@ -86,6 +87,11 @@ static struct cpuidle_params cpuidle_params_table[] = {
       {1, 10000, 30000, 300000},
 };
+#ifdef CONFIG_CPU_IDLE_PROF
+static struct clk *clk_32k;
+#define CONVERT_32K_USEC(lat) (lat * (USEC_PER_SEC/clk_get_rate(clk_32k)))
+#endif



static int omap3_idle_bm_check(void)
 {
       if (!omap3_can_sleep())
@@ -115,21 +121,28 @@ static int _cpuidle_deny_idle(struct powerdomain
*pwrdm,
...

Called from the CPUidle framework to program the device to the
specified target state selected by the governor.

*/



static int omap3_enter_idle(struct cpuidle_device *dev,
                       struct cpuidle_state *state)
 {
       struct omap3_processor_cx *cx = cpuidle_get_statedata(state);
       struct timespec ts_preidle, ts_postidle, ts_idle;
       u32 mpu_state = cx->mpu_state, core_state = cx->core_state;
+#ifdef CONFIG_CPU_IDLE_PROF

  int idle_time, latency;


  long sleep_time, wkup_time, total_sleep_time;


  long preidle_time, postidle_time;



+#endif
   current_cx_state = *cx;



  /* Used to keep track of the total time in idle */


  getnstimeofday(&ts_preidle);


 local_irq_disable();
 local_fiq_disable();





  /* Used to keep track of the total time in idle */


  getnstimeofday(&ts_preidle);



+#ifdef CONFIG_CPU_IDLE_PROF

  preidle_time = omap3_sram_get_32k_tick();



+#endif
       pwrdm_set_next_pwrst(mpu_pd, mpu_state);
       pwrdm_set_next_pwrst(core_pd, core_state);
@@ -153,9 +166,39 @@ return_sleep_time:
       getnstimeofday(&ts_postidle);
       ts_idle = timespec_sub(ts_postidle, ts_preidle);
+#ifdef CONFIG_CPU_IDLE_PROF

  postidle_time = omap3_sram_get_32k_tick();



+#endif
       local_irq_enable();
       local_fiq_enable();
+#ifdef CONFIG_CPU_IDLE_PROF

  sleep_time = omap3_sram_get_sleep_time();


  wkup_time = omap3_sram_get_wkup_time();



  /* take care of overflow */


  if (postidle_time < preidle_time)


          postidle_time += (u32) 0xffffffff;


  if (wkup_time < sleep_time)


          wkup_time += (u32) 0xffffffff;



  idle_time = postidle_time - preidle_time;


  total_sleep_time = wkup_time -  sleep_time;


  latency = idle_time - total_sleep_time;


  sleep_time = omap3_sram_get_sleep_time();


  wkup_time = omap3_sram_get_wkup_time();



  /* calculate average latency after ignoring sprious ones */


  if ((total_sleep_time > 0) && (latency > state->actual_latency)


          && (latency >= 0)) {


          state->actual_latency = CONVERT_32K_USEC(latency);


          latency = (sleep_time - preidle_time);


          state->sleep_latency = CONVERT_32K_USEC(latency);


          latency = postidle_time - wkup_time;


          state->wkup_latency = CONVERT_32K_USEC(latency);


  }



+#endif

 return ts_idle.tv_nsec / NSEC_PER_USEC + ts_idle.tv_sec * USEC_PER_SEC;



}
@@ -423,7 +466,9 @@ int __init omap3_idle_init(void)
       struct omap3_processor_cx *cx;
       struct cpuidle_state *state;
       struct cpuidle_device *dev;



+#ifdef CONFIG_CPU_IDLE_PROF

  static struct device dummy_device;



+#endif
       mpu_pd = pwrdm_lookup("mpu_pwrdm");
       core_pd = pwrdm_lookup("core_pwrdm");
@@ -456,6 +501,9 @@ int __init omap3_idle_init(void)
   omap3_cpuidle_update_states();


+#ifdef CONFIG_CPU_IDLE_PROF

  clk_32k = clk_get(&dummy_device, "wkup_32k_fck");



+#endif
       if (cpuidle_register_device(dev)) {
               printk(KERN_ERR "%s: CPUidle register device failed\n",
                      __func__);
diff --git a/arch/arm/mach-omap2/pm.h b/arch/arm/mach-omap2/pm.h
index 3de6ece..e62e87d 100644
--- a/arch/arm/mach-omap2/pm.h
+++ b/arch/arm/mach-omap2/pm.h
@@ -82,4 +82,9 @@ extern unsigned int save_secure_ram_context_sz;
 extern unsigned int omap24xx_cpu_suspend_sz;
 extern unsigned int omap34xx_cpu_suspend_sz;
+#ifdef CONFIG_CPU_IDLE_PROF
+extern u32 omap3_sram_get_wkup_time();
+extern u32 omap3_sram_get_sleep_time();
+extern u32 omap3_sram_get_32k_tick();
+#endif
 #endif
diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-
omap2/sleep34xx.S
...
index d522cd7..8dec5ef 100644
--- a/arch/arm/mach-omap2/sleep34xx.S
+++ b/arch/arm/mach-omap2/sleep34xx.S
@@ -59,6 +59,20 @@
 #define SDRC_DLLA_STATUS_V
OMAP34XX_SDRC_REGADDR(SDRC_DLLA_STATUS)
...
#define SDRC_DLLA_CTRL_V       OMAP34XX_SDRC_REGADDR(SDRC_DLLA_CTRL)
+#define TIMER_32K_SYNC_P       0x48320010
+#define TIMER_32K_SYNC         OMAP2_L4_IO_ADDRESS(TIMER_32K_SYNC_P)



+#define SCRATCHPAD_SLEEP_TIME_OFFSET 0x9f8
+#define SCRATCHPAD_WKUP_TIME_OFFSET 0x9fc
+#define SCRATCHPAD_SLEEP_TIME
OMAP343X_CTRL_REGADDR(SCRATCHPAD_SLEEP_TIME_OFFSET)
...
+#define SCRATCHPAD_WKUP_TIME
OMAP343X_CTRL_REGADDR(SCRATCHPAD_WKUP_TIME_OFFSET)
...
+#define SCRATCHPAD_WKUP_TIME_P OMAP343X_CTRL_BASE +
SCRATCHPAD_WKUP_TIME_OFFSET
...



+#define CM_ICLKEN_WKUP OMAP34XX_CM_REGADDR(WKUP_MOD, CM_ICLKEN)
+#define CM_ICLKEN_WKUP_P       OMAP3430_CM_BASE + WKUP_MOD +
CM_ICLKEN
...
+#define CM_IDLEST_WKUP OMAP34XX_CM_REGADDR(WKUP_MOD, CM_IDLEST)
+#define CM_IDLEST_WKUP_P       OMAP3430_CM_BASE + WKUP_MOD +
CM_IDLEST
...

  .text



/* Function to aquire the semaphore in scratchpad */
 ENTRY(lock_scratchpad_sem)
@@ -183,7 +197,31 @@ api_params:
       .word   0x4, 0x0, 0x0, 0x1, 0x1
 ENTRY(save_secure_ram_context_sz)
       .word   . - save_secure_ram_context
+#ifdef CONFIG_CPU_IDLE_PROF
+ENTRY(omap3_sram_get_wkup_time)

stmfd   sp!, {lr}     @ save registers on stack
  ldr r0, wkup_time


  ldr r0, [r0]


ldmfd   sp!, {pc}     @ restore regs and return

+ENTRY(omap3_sram_get_wkup_time_sz)

   .word   . - omap3_sram_get_wkup_time




+ENTRY(omap3_sram_get_sleep_time)

stmfd   sp!, {lr}     @ save registers on stack
  ldr r0, sleep_time


  ldr r0, [r0]


ldmfd   sp!, {pc}     @ restore regs and return

+ENTRY(omap3_sram_get_sleep_time_sz)

   .word   . - omap3_sram_get_sleep_time




+ENTRY(omap3_sram_get_32k_tick)

stmfd   sp!, {lr}     @ save registers on stack
  ldr r0, sync_32k_timer


  ldr r0, [r0]


ldmfd   sp!, {pc}     @ restore regs and return

+ENTRY(omap3_sram_get_32k_tick_sz)

   .word   . - omap3_sram_get_32k_tick



+#endif
 /*

Forces OMAP into idle state


@@ -207,6 +245,13 @@ loop:
       cmp     r1, #0x0
       /* If context save is required, do that and execute wfi */
       bne     save_context_wfi



+#ifdef CONFIG_CPU_IDLE_PROF

  ldr r4, sync_32k_timer


  ldr     r5, [r4]


  ldr r6, sleep_time


  str r5, [r6]



+#endif
       /* Data memory barrier and Data sync barrier */
       mov     r1, #0
       mcr     p15, 0, r1, c7, c10, 4
@@ -224,8 +269,25 @@ loop:
       nop
       nop
       nop
+#ifdef CONFIG_CPU_IDLE_PROF

  ldr r4, iclken_wkup


  ldr r5, [r4]


  orr r5, r5, #0x4


  str r5, [r4]


  ldr r4, idlest_wkup



+wait_idlest:

  ldr r5, [r4]


  and     r5, r5, #0x4


  cmp     r5, #0x0


  bne     wait_idlest


  ldr r4, sync_32k_timer


  ldr     r5, [r4]


  ldr r6, wkup_time


  str r5, [r6]



+#endif
       bl wait_sdrc_ok

 ldmfd   sp!, {r0-r12, pc}               @ restore regs and return



restore_es3:
       /*b restore_es3*/               @ Enable to debug restore code
@@ -247,6 +309,23 @@ copy_to_sram:
       blx     r1
 restore:
       /* b restore*/  @ Enable to debug restore code
+#ifdef CONFIG_CPU_IDLE_PROF

  ldr r4, iclken_wkup_p


  ldr r5, [r4]


  orr r5, r5, #0x4


  str r5, [r4]


  ldr r4, idlest_wkup_p



+wait_idlest1:

  ldr r5, [r4]


  and     r5, r5, #0x4


  cmp     r5, #0x0


  bne     wait_idlest1


  ldr r4, sync_32k_timer_p


  ldr r5, [r4]


  ldr r6, wkup_time_p


  str r5, [r6]



+#endif

  /* Check what was the reason for mpu reset and store the reason in r9*/
  /* 1 - Only L1 and logic lost */
  /* 2 - Only L2 lost - In this case, we wont be here */



@@ -587,6 +666,12 @@ finished:
       mcr     p15, 2, r10, c0, c0, 0
       isb
 skip_l2_inval:
+#ifdef CONFIG_CPU_IDLE_PROF

  ldr r4, sync_32k_timer


  ldr     r5, [r4]


  ldr r6, sleep_time


  str r5, [r6]



+#endif
       /* Data memory barrier and Data sync barrier */
       mov     r1, #0
       mcr     p15, 0, r1, c7, c10, 4
@@ -603,6 +688,22 @@ skip_l2_inval:
       nop
       nop
       nop
+#ifdef CONFIG_CPU_IDLE_PROF

  ldr r4, iclken_wkup


  ldr r5, [r4]


  orr r5, r5, #0x4


  str r5, [r4]


  ldr r4, idlest_wkup



+wait_idlest2:

  ldr r5, [r4]


  and     r5, r5, #0x4


  cmp     r5, #0x0


  bne     wait_idlest2


  ldr r4, sync_32k_timer


  ldr     r5, [r4]


  ldr r6, wkup_time


  str r5, [r6]



+#endif
       bl wait_sdrc_ok
       /* restore regs and return */
       ldmfd   sp!, {r0-r12, pc}
@@ -668,5 +769,25 @@ cache_pred_disable_mask:
       .word   0xFFFFE7FB
 control_stat:
       .word   CONTROL_STAT
+#ifdef CONFIG_CPU_IDLE_PROF
+sync_32k_timer:

  .word TIMER_32K_SYNC



+sync_32k_timer_p:

  .word TIMER_32K_SYNC_P



+sleep_time:

  .word SCRATCHPAD_SLEEP_TIME



+wkup_time:

  .word SCRATCHPAD_WKUP_TIME



+wkup_time_p:

  .word SCRATCHPAD_WKUP_TIME_P



+iclken_wkup:

  .word CM_ICLKEN_WKUP



+iclken_wkup_p:

  .word CM_ICLKEN_WKUP_P



+idlest_wkup:

  .word CM_IDLEST_WKUP



+idlest_wkup_p:

  .word CM_IDLEST_WKUP_P



+#endif
 ENTRY(omap34xx_cpu_suspend_sz)
       .word   . - omap34xx_cpu_suspend
diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index 7dbc4a8..147456d 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -18,3 +18,8 @@ config CPU_IDLE_GOV_MENU
       bool
       depends on CPU_IDLE && NO_HZ
       default y



+config CPU_IDLE_PROF

  bool



Should not this be something like bool "CPU idle profiling " so that
this entry shows up in
'make menuconfig' ? and this should have dependency on ARCH_OMAP3 also ?
Thanks. Will fix it in V2.
Vishwa
...
...

  depends on CPU_IDLE


  default n



diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index 0310ffa..a3e9db1 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -249,6 +249,11 @@ define_show_state_ull_function(usage)
 define_show_state_ull_function(time)
 define_show_state_str_function(name)
 define_show_state_str_function(desc)
+#ifdef CONFIG_CPU_IDLE_PROF
+define_show_state_function(actual_latency)
+define_show_state_function(sleep_latency)
+define_show_state_function(wkup_latency)
+#endif
define_one_state_ro(name, show_state_name);
 define_one_state_ro(desc, show_state_desc);
@@ -256,7 +261,11 @@ define_one_state_ro(latency, show_state_exit_latency);
 define_one_state_ro(power, show_state_power_usage);
 define_one_state_ro(usage, show_state_usage);
 define_one_state_ro(time, show_state_time);



+#ifdef CONFIG_CPU_IDLE_PROF
+define_one_state_ro(actual_latency, show_state_actual_latency);
+define_one_state_ro(sleep_latency, show_state_sleep_latency);
+define_one_state_ro(wkup_latency, show_state_wkup_latency);
+#endif
 static struct attribute *cpuidle_state_default_attrs[] = {
       &attr_name.attr,
       &attr_desc.attr,
@@ -264,6 +273,11 @@ static struct attribute *cpuidle_state_default_attrs[] = {
       &attr_power.attr,
       &attr_usage.attr,
       &attr_time.attr,
+#ifdef CONFIG_CPU_IDLE_PROF

  &attr_actual_latency.attr,


  &attr_sleep_latency.attr,


  &attr_wkup_latency.attr,



+#endif
       NULL
 };
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 55215cc..6474f6a 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -43,6 +43,9 @@ struct cpuidle_state {
   int (*enter)    (struct cpuidle_device *dev,
                    struct cpuidle_state *state);

+#ifdef CONFIG_CPU_IDLE_PROF

  u32 actual_latency, sleep_latency, wkup_latency;



+#endif
 };
/* Idle State Flags */
1.7.0.4
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--
Silesh
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RE: [PATCH] OMAP CPUIDLE: CPU Idle latency measurement

/* Idle State Flags */