Hi Todd,
On 06/18/18 18:46, Todd Poynor wrote:
> From: Todd Poynor <toddpoynor@xxxxxxxxxx>
>
> Add initcall_debug logs for the amount of time taken by each OF platform
> bus device create call. For example:
>
> of platform device create /reserved-memory/ramoops@a3800000 took
> 3255 usecs
>
> initcall_debug already reports the total of all such device creates
> as a single entry for function of_platform_default_populate_init (or
> similar, depending on the board). The new logs help identify which of
> the potentially hundreds of device inits take significant amounts of
> time.
>
> Signed-off-by: Todd Poynor <toddpoynor@xxxxxxxxxx>
> ---
> drivers/of/platform.c | 28 +++++++++++++++++++++++++++-
> 1 file changed, 27 insertions(+), 1 deletion(-)
>
> Note it's likely only a few devices take significant lengths of time to
> init, whereas there may be hundreds of uninteresting cases also logged.
> Adding a threshold for reporting might be desirable, although for boot
> time sleuthing it's probably fine to generate a ton of output and narrow
> down the points of interest with tools.
>
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 6925d993e1f0..eeb4c595f43c 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -14,6 +14,7 @@
> #include <linux/amba/bus.h>
> #include <linux/device.h>
> #include <linux/dma-mapping.h>
> +#include <linux/init.h>
> #include <linux/slab.h>
> #include <linux/of_address.h>
> #include <linux/of_device.h>
> @@ -159,6 +160,19 @@ struct platform_device *of_device_alloc(struct device_node *np,
> }
> EXPORT_SYMBOL(of_device_alloc);
>
> +static void of_platform_log_inittime(struct device_node *node,
> + ktime_t starttime)
Please call it pr_delta_time() instead.
> +{
> + ktime_t delta, endtime;
> + unsigned long long duration;
> +
> + endtime = ktime_get();
> + delta = ktime_sub(endtime, starttime);
> + duration = (unsigned long long) ktime_to_ns(delta) >> 10;
> + pr_debug("of platform device create %s took %lld usecs\n",
> + node->full_name, duration);
The device node full_name field no longer contains the full path of
the node name. To deal with this, use %pOF on node instead of
%s on node->full_name (core-api/printk-formats.rst).
> +}
> +
> /**
> * of_platform_device_create_pdata - Alloc, initialize and register an of_device
> * @np: pointer to node to create device for
> @@ -176,6 +190,8 @@ static struct platform_device *of_platform_device_create_pdata(
> struct device *parent)
> {
> struct platform_device *dev;
> + ktime_t starttime = 0;
I assume the initialization to zero is to silence a compiler warning. Is my
assumption correct?
> + int ret;
>
> if (!of_device_is_available(np) ||
> of_node_test_and_set_flag(np, OF_POPULATED))
> @@ -187,9 +203,14 @@ static struct platform_device *of_platform_device_create_pdata(
>
> dev->dev.bus = &platform_bus_type;
> dev->dev.platform_data = platform_data;
> + if (initcall_debug)
> + starttime = ktime_get();
> of_msi_configure(&dev->dev, dev->dev.of_node);
> + ret = of_device_add(dev);
> + if (initcall_debug)
> + of_platform_log_inittime(np, starttime);
>
> - if (of_device_add(dev) != 0) {
> + if (ret != 0) {
> platform_device_put(dev);
> goto err_clear_flag;
> }
> @@ -352,6 +373,7 @@ static int of_platform_bus_create(struct device_node *bus,
> struct platform_device *dev;
> const char *bus_id = NULL;
> void *platform_data = NULL;
> + ktime_t starttime = 0;
> int rc = 0;
>
> /* Make sure it has a compatible property */
> @@ -384,7 +406,11 @@ static int of_platform_bus_create(struct device_node *bus,
> * Don't return an error here to keep compatibility with older
> * device tree files.
> */
> + if (initcall_debug)
> + starttime = ktime_get();
> of_amba_device_create(bus, bus_id, platform_data, parent);
> + if (initcall_debug)
> + of_platform_log_inittime(bus, starttime);
> return 0;
> }
>
>
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