Re: [PATCH v4 17/24] PM / devfreq: tegra30: Use tracepoints for debugging

Chanwoo Choi
2019-07-18T09:44:09Z

On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote:
> Debug messages create too much CPU and memory activity by themselves,
> so it's difficult to debug lower rates and catch unwanted interrupts
> that happen rarely. Tracepoints are ideal in that regards because they
> do not contribute to the sampled date at all. This allowed me to catch
> few problems which are fixed by the followup patches, without tracepoints
> it would be much harder to do.
>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> drivers/devfreq/tegra30-devfreq.c | 43 +++-------
> include/trace/events/tegra30_devfreq.h | 105 +++++++++++++++++++++++++
> 2 files changed, 117 insertions(+), 31 deletions(-)
> create mode 100644 include/trace/events/tegra30_devfreq.h

As I knew, 'include/trace/events' don't include the header file
for only one device driver. Usually, the trace event is provided
by framework instead of each devic driver.

>
> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
> index 6ebf0f505767..43c9c5fbfe91 100644
> --- a/drivers/devfreq/tegra30-devfreq.c
> +++ b/drivers/devfreq/tegra30-devfreq.c
> @@ -19,6 +19,9 @@
> #include <linux/reset.h>
> #include <linux/workqueue.h>
>
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/tegra30_devfreq.h>
> +
> #include "governor.h"
>
> #define ACTMON_GLB_STATUS 0x0
> @@ -283,9 +286,6 @@ static void tegra_actmon_get_lower_upper(struct tegra_devfreq *tegra,
> unsigned long *lower,
> unsigned long *upper)
> {
> - struct device *ddev = tegra->devfreq->dev.parent;
> - u32 offset = dev->config->offset;
> -
> /*
> * Memory frequencies are guaranteed to have 1MHz granularity
> * and thus we need this rounding down to get a proper watermarks
> @@ -298,8 +298,8 @@ static void tegra_actmon_get_lower_upper(struct tegra_devfreq *tegra,
> *lower = tegra_actmon_lower_freq(tegra, target_freq);
> *upper = tegra_actmon_upper_freq(tegra, target_freq);
>
> - dev_dbg(ddev, "%03x: target_freq %lu lower freq %lu upper freq %lu\n",
> - offset, target_freq, *lower, *upper);
> + trace_device_lower_upper(dev->config->offset, target_freq,
> + *lower, *upper);
>
> /*
> * The upper watermark should take into account CPU's frequency
> @@ -377,30 +377,13 @@ static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
> device_writel(dev, lower + delta, ACTMON_DEV_LOWER_WMARK);
> }
>
> -static void actmon_device_debug(struct tegra_devfreq *tegra,
> - struct tegra_devfreq_device *dev,
> - const char *prefix)
> -{
> - dev_dbg(tegra->devfreq->dev.parent,
> - "%03x: %s: 0x%08x 0x%08x a %u %u %u c %u %u %u b %lu cpu %u\n",
> - dev->config->offset, prefix,
> - device_readl(dev, ACTMON_DEV_INTR_STATUS),
> - device_readl(dev, ACTMON_DEV_CTRL),
> - device_readl(dev, ACTMON_DEV_AVG_COUNT),
> - device_readl(dev, ACTMON_DEV_AVG_LOWER_WMARK),
> - device_readl(dev, ACTMON_DEV_AVG_UPPER_WMARK),
> - device_readl(dev, ACTMON_DEV_COUNT),
> - device_readl(dev, ACTMON_DEV_LOWER_WMARK),
> - device_readl(dev, ACTMON_DEV_UPPER_WMARK),
> - dev->boost_freq, cpufreq_get(0));
> -}
> -
> static void actmon_isr_device(struct tegra_devfreq *tegra,
> struct tegra_devfreq_device *dev)
> {
> u32 intr_status, dev_ctrl, avg_intr_mask, avg_count;
>
> - actmon_device_debug(tegra, dev, "isr+");
> + trace_device_isr_enter(tegra->regs, dev->config->offset,
> + dev->boost_freq, cpufreq_get(0));
>
> intr_status = device_readl(dev, ACTMON_DEV_INTR_STATUS);
> avg_count = device_readl(dev, ACTMON_DEV_AVG_COUNT);
> @@ -455,7 +438,8 @@ static void actmon_isr_device(struct tegra_devfreq *tegra,
> device_writel(dev, dev_ctrl, ACTMON_DEV_CTRL);
> device_writel(dev, ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS);
>
> - actmon_device_debug(tegra, dev, "isr-");
> + trace_device_isr_exit(tegra->regs, dev->config->offset,
> + dev->boost_freq, cpufreq_get(0));
> }
>
> static unsigned long actmon_update_target(struct tegra_devfreq *tegra,
> @@ -749,7 +733,6 @@ static struct devfreq_dev_profile tegra_devfreq_profile = {
> static int tegra_governor_get_target(struct devfreq *devfreq,
> unsigned long *freq)
> {
> - struct device *ddev = devfreq->dev.parent;
> struct devfreq_dev_status *stat;
> struct tegra_devfreq *tegra;
> struct tegra_devfreq_device *dev;
> @@ -770,13 +753,11 @@ static int tegra_governor_get_target(struct devfreq *devfreq,
> dev = &tegra->devices[i];
>
> dev_target_freq = actmon_update_target(tegra, dev);
> -
> target_freq = max(target_freq, dev_target_freq);
>
> - dev_dbg(ddev, "%03x: upd: dev_target_freq %lu\n",
> - dev->config->offset, dev_target_freq);
> -
> - actmon_device_debug(tegra, dev, "upd");
> + trace_device_target_freq(dev->config->offset, dev_target_freq);
> + trace_device_target_update(tegra->regs, dev->config->offset,
> + dev->boost_freq, cpufreq_get(0));
> }
>
> *freq = target_freq;
> diff --git a/include/trace/events/tegra30_devfreq.h b/include/trace/events/tegra30_devfreq.h
> new file mode 100644
> index 000000000000..8f264a489daf
> --- /dev/null
> +++ b/include/trace/events/tegra30_devfreq.h
> @@ -0,0 +1,105 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM tegra30_devfreq
> +
> +#if !defined(_TRACE_TEGRA30_DEVFREQ_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_TEGRA30_DEVFREQ_H
> +
> +#include <linux/io.h>
> +#include <linux/tracepoint.h>
> +#include <linux/types.h>
> +
> +DECLARE_EVENT_CLASS(device_state,
> + TP_PROTO(void __iomem *base, u32 offset, u32 boost, u32 cpufreq),
> + TP_ARGS(base, offset, boost, cpufreq),
> + TP_STRUCT__entry(
> + __field(u32, offset)
> + __field(u32, intr_status)
> + __field(u32, ctrl)
> + __field(u32, avg_count)
> + __field(u32, avg_lower)
> + __field(u32, avg_upper)
> + __field(u32, count)
> + __field(u32, lower)
> + __field(u32, upper)
> + __field(u32, boost_freq)
> + __field(u32, cpu_freq)
> + ),
> + TP_fast_assign(
> + __entry->offset = offset;
> + __entry->intr_status = readl_relaxed(base + offset + 0x24);
> + __entry->ctrl = readl_relaxed(base + offset + 0x0);
> + __entry->avg_count = readl_relaxed(base + offset + 0x20);
> + __entry->avg_lower = readl_relaxed(base + offset + 0x14);
> + __entry->avg_upper = readl_relaxed(base + offset + 0x10);
> + __entry->count = readl_relaxed(base + offset + 0x1c);
> + __entry->lower = readl_relaxed(base + offset + 0x8);
> + __entry->upper = readl_relaxed(base + offset + 0x4);
> + __entry->boost_freq = boost;
> + __entry->cpu_freq = cpufreq;
> + ),
> + TP_printk("%03x: intr 0x%08x ctrl 0x%08x avg %010u %010u %010u cnt %010u %010u %010u boost %010u cpu %u",
> + __entry->offset,
> + __entry->intr_status,
> + __entry->ctrl,
> + __entry->avg_count,
> + __entry->avg_lower,
> + __entry->avg_upper,
> + __entry->count,
> + __entry->lower,
> + __entry->upper,
> + __entry->boost_freq,
> + __entry->cpu_freq)
> +);
> +
> +DEFINE_EVENT(device_state, device_isr_enter,
> + TP_PROTO(void __iomem *base, u32 offset, u32 boost, u32 cpufreq),
> + TP_ARGS(base, offset, boost, cpufreq));
> +
> +DEFINE_EVENT(device_state, device_isr_exit,
> + TP_PROTO(void __iomem *base, u32 offset, u32 boost, u32 cpufreq),
> + TP_ARGS(base, offset, boost, cpufreq));
> +
> +DEFINE_EVENT(device_state, device_target_update,
> + TP_PROTO(void __iomem *base, u32 offset, u32 boost, u32 cpufreq),
> + TP_ARGS(base, offset, boost, cpufreq));
> +
> +TRACE_EVENT(device_lower_upper,
> + TP_PROTO(u32 offset, u32 target, u32 lower, u32 upper),
> + TP_ARGS(offset, target, lower, upper),
> + TP_STRUCT__entry(
> + __field(u32, offset)
> + __field(u32, target)
> + __field(u32, lower)
> + __field(u32, upper)
> + ),
> + TP_fast_assign(
> + __entry->offset = offset;
> + __entry->target = target;
> + __entry->lower = lower;
> + __entry->upper = upper;
> + ),
> + TP_printk("%03x: freq %010u lower freq %010u upper freq %010u",
> + __entry->offset,
> + __entry->target,
> + __entry->lower,
> + __entry->upper)
> +);
> +
> +TRACE_EVENT(device_target_freq,
> + TP_PROTO(u32 offset, u32 target),
> + TP_ARGS(offset, target),
> + TP_STRUCT__entry(
> + __field(u32, offset)
> + __field(u32, target)
> + ),
> + TP_fast_assign(
> + __entry->offset = offset;
> + __entry->target = target;
> + ),
> + TP_printk("%03x: freq %010u", __entry->offset, __entry->target)
> +);
> +#endif /* _TRACE_TEGRA30_DEVFREQ_H */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
>

--
Best Regards,
Chanwoo Choi
Samsung Electronics