bitbake: runqueue.py: fix PSI check logic

The current calculation is not correct because if tdiff is less than
1.0, it's not taken into consideration when calculating the current
pressure.

Also, make it clear that the 1.0s is the psi accumulation cycle,
which might be changed in the future. We have this cycle because it
could largely avoid the 0 result issue, that is, if the interval
between checks are too small, the result might be 0. With this
accumulation logic, which has been there but let's make it clear,
this 0 result problem could be mitigated.

(Bitbake rev: 76889ff0a8938a3d77603d2af176aa9e264df839)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/bitbake/lib/bb/runqueue.py b/bitbake/lib/bb/runqueue.py
index ab9e3fbe83..830af8eef4 100644
--- a/bitbake/lib/bb/runqueue.py
+++ b/bitbake/lib/bb/runqueue.py
@@ -200,7 +200,8 @@ class RunQueueScheduler(object):
                 curr_memory_pressure = memory_pressure_fds.readline().split()[4].split("=")[1]
                 now = time.time()
                 tdiff = now - self.prev_pressure_time
-                if tdiff > 1.0:
+                psi_accumulation_interval = 1.0
+                if tdiff > psi_accumulation_interval:
                     exceeds_cpu_pressure =  self.rq.max_cpu_pressure and (float(curr_cpu_pressure) - float(self.prev_cpu_pressure)) / tdiff > self.rq.max_cpu_pressure
                     exceeds_io_pressure =  self.rq.max_io_pressure and (float(curr_io_pressure) - float(self.prev_io_pressure)) / tdiff > self.rq.max_io_pressure
                     exceeds_memory_pressure = self.rq.max_memory_pressure and (float(curr_memory_pressure) - float(self.prev_memory_pressure)) / tdiff > self.rq.max_memory_pressure
@@ -209,9 +210,9 @@ class RunQueueScheduler(object):
                     self.prev_memory_pressure = curr_memory_pressure
                     self.prev_pressure_time = now
                 else:
-                    exceeds_cpu_pressure =  self.rq.max_cpu_pressure and (float(curr_cpu_pressure) - float(self.prev_cpu_pressure)) > self.rq.max_cpu_pressure
-                    exceeds_io_pressure =  self.rq.max_io_pressure and (float(curr_io_pressure) - float(self.prev_io_pressure)) > self.rq.max_io_pressure
-                    exceeds_memory_pressure = self.rq.max_memory_pressure and (float(curr_memory_pressure) - float(self.prev_memory_pressure)) > self.rq.max_memory_pressure
+                    exceeds_cpu_pressure =  self.rq.max_cpu_pressure and (float(curr_cpu_pressure) - float(self.prev_cpu_pressure)) / tdiff > self.rq.max_cpu_pressure
+                    exceeds_io_pressure =  self.rq.max_io_pressure and (float(curr_io_pressure) - float(self.prev_io_pressure)) / tdiff > self.rq.max_io_pressure
+                    exceeds_memory_pressure = self.rq.max_memory_pressure and (float(curr_memory_pressure) - float(self.prev_memory_pressure)) / tdiff > self.rq.max_memory_pressure
             pressure_state = (exceeds_cpu_pressure, exceeds_io_pressure, exceeds_memory_pressure)
             if hasattr(self, "pressure_state") and pressure_state != self.pressure_state:
                 bb.note("Pressure status changed to CPU: %s, IO: %s, Mem: %s" % pressure_state)