[PATCH v2 2/2] dts: avoid dpdk resources conflict

[Patrick Robb]

When starting and stopping DPDK applications in rapid succession,
there may be a resource conflicts on ports, memory, VFIO, etc.
Even after we send "quit" to the testpmd CLI, some resource
cleanup will happen asynchronously in the background. To avoid a
resource conflict upon starting a subsequent DPDK application,
add a very brief sleep after quitting DPDK applications.

Fixes: bfad0948df75 ("dts: rework interactive shells")

Signed-off-by: Patrick Robb <probb at iol.unh.edu>
Tested-by: Patrick Robb <probb at iol.unh.edu>
---
 dts/api/testpmd/__init__.py                |  2 +-
 dts/framework/remote_session/dpdk_shell.py | 12 +++++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/dts/api/testpmd/__init__.py b/dts/api/testpmd/__init__.py
index 703cae487e..e9187440bb 100644
--- a/dts/api/testpmd/__init__.py
+++ b/dts/api/testpmd/__init__.py
@@ -1174,7 +1174,7 @@ def clear_port_stats_all(self, verify: bool = True) -> None:
 
     @only_active
     def close(self) -> None:
-        """Overrides :meth:`~.interactive_shell.close`."""
+        """Overrides :meth:`~.dpdk_shell.close`."""
         self.stop()
         self.send_command("quit", "Bye...")
         return super().close()
diff --git a/dts/framework/remote_session/dpdk_shell.py b/dts/framework/remote_session/dpdk_shell.py
index 51b97d4ff6..f926c3fa4d 100644
--- a/dts/framework/remote_session/dpdk_shell.py
+++ b/dts/framework/remote_session/dpdk_shell.py
@@ -6,13 +6,14 @@
 Provides a base class to create interactive shells based on DPDK.
 """
 
+import time
 from abc import ABC, abstractmethod
 from pathlib import PurePath
 
 from framework.context import get_ctx
 from framework.params.eal import EalParams
 from framework.remote_session.interactive_shell import (
-    InteractiveShell,
+    InteractiveShell, only_active,
 )
 from framework.testbed_model.cpu import LogicalCoreList
 
@@ -84,3 +85,12 @@ def _make_real_path(self) -> PurePath:
         Adds the remote DPDK build directory to the path.
         """
         return get_ctx().dpdk_build.remote_dpdk_build_dir.joinpath(self.path)
+
+    @only_active
+    def close(self) -> None:
+        """Overrides :meth:`~.interactive_shell.close`."""
+        # Allow time for VFIO and hardware resources to be released by the kernel after the
+        # DPDK process exits. Without this delay, sequential testpmd instances may have EAL
+        # errors when trying to acquire the same devices.
+        time.sleep(1)
+        return super().close()
-- 
2.49.0