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intel_th: msu: Make stopping the trace optional

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Some use cases prefer to keep collecting the trace data into the last
available window while the other windows are being offloaded instead of
stopping the trace. In this scenario, the window switch happens
automatically when the next window becomes available again.

Add an option to allow this and a sysfs attribute to enable it.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200319085152.52183-1-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Shishkin 2020-03-19 10:51:52 +02:00 committed by Greg Kroah-Hartman
parent 3baf89abca
commit 8622dfefb6
2 changed files with 45 additions and 1 deletions
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8
Documentation/ABI/testing/sysfs-bus-intel_th-devices-msc
View File

@ -40,3 +40,11 @@ Description: (RW) Trigger window switch for the MSC's buffer, in
triggering a window switch for the buffer. Returns an error in any
other operating mode or attempts to write something other than "1".
What: /sys/bus/intel_th/devices/<intel_th_id>-msc<msc-id>/stop_on_full
Date: March 2020
KernelVersion: 5.7
Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Description: (RW) Configure whether trace stops when the last available window
becomes full (1/y/Y) or wraps around and continues until the next
window becomes available again (0/n/N).

38
drivers/hwtracing/intel_th/msu.c
View File

@ -138,6 +138,7 @@ struct msc {
struct list_head win_list;
struct sg_table single_sgt;
struct msc_window *cur_win;
struct msc_window *switch_on_unlock;
unsigned long nr_pages;
unsigned long single_sz;
unsigned int single_wrap : 1;
@ -154,6 +155,8 @@ struct msc {
struct list_head iter_list;
bool stop_on_full;
/* config */
unsigned int enabled : 1,
wrap : 1,
@ -1718,6 +1721,10 @@ void intel_th_msc_window_unlock(struct device *dev, struct sg_table *sgt)
return;
msc_win_set_lockout(win, WIN_LOCKED, WIN_READY);
if (msc->switch_on_unlock == win) {
msc->switch_on_unlock = NULL;
msc_win_switch(msc);
}
}
EXPORT_SYMBOL_GPL(intel_th_msc_window_unlock);
@ -1758,7 +1765,11 @@ static irqreturn_t intel_th_msc_interrupt(struct intel_th_device *thdev)
/* next window: if READY, proceed, if LOCKED, stop the trace */
if (msc_win_set_lockout(next_win, WIN_READY, WIN_INUSE)) {
schedule_work(&msc->work);
if (msc->stop_on_full)
schedule_work(&msc->work);
else
msc->switch_on_unlock = next_win;
return IRQ_HANDLED;
}
@ -2051,11 +2062,36 @@ win_switch_store(struct device *dev, struct device_attribute *attr,
static DEVICE_ATTR_WO(win_switch);
static ssize_t stop_on_full_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct msc *msc = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", msc->stop_on_full);
}
static ssize_t stop_on_full_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct msc *msc = dev_get_drvdata(dev);
int ret;
ret = kstrtobool(buf, &msc->stop_on_full);
if (ret)
return ret;
return size;
}
static DEVICE_ATTR_RW(stop_on_full);
static struct attribute *msc_output_attrs[] = {
&dev_attr_wrap.attr,
&dev_attr_mode.attr,
&dev_attr_nr_pages.attr,
&dev_attr_win_switch.attr,
&dev_attr_stop_on_full.attr,
NULL,
};