[dpdk-stable] patch 'eal: restrict control threads to startup CPU affinity' has been queued to LTS release 18.11.2

[Kevin Traynor <ktraynor@redhat.com>]

Hi,

FYI, your patch has been queued to LTS release 18.11.2

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 04/16/19. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Thanks.

Kevin Traynor

---
From 23a9f69ed3d9c98b1912df305552ed6dbc639e8f Mon Sep 17 00:00:00 2001
From: David Marchand <david.marchand@redhat.com>
Date: Tue, 19 Feb 2019 21:41:11 +0100
Subject: [PATCH] eal: restrict control threads to startup CPU affinity

[ upstream commit c3568ea376700df061abcbeabc40ddaed7841e1a ]

Spawning the ctrl threads on anything that is not part of the eal
coremask is not that polite to the rest of the system, especially
when you took good care to pin your processes on cpu resources with
tools like taskset (linux) / cpuset (freebsd).

Rather than introduce yet another eal options to control on which cpu
those ctrl threads are created, let's take the startup cpu affinity
as a reference and remove the eal coremask from it.
If no cpu is left, then we default to the master core.

The cpuset is computed once at init before the original cpu affinity
is lost.

Introduced a RTE_CPU_AND macro to abstract the differences between linux
and freebsd respective macros.

Examples in a 4 cores FreeBSD vm:

$ ./build/app/testpmd -l 2,3 --no-huge --no-pci -m 512 \
 -- -i --total-num-mbufs=2048

$ procstat -S 1057
  PID    TID COMM                TDNAME              CPU CSID CPU MASK
 1057 100131 testpmd             -                     2    1 2
 1057 100140 testpmd             eal-intr-thread       1    1 0-1
 1057 100141 testpmd             rte_mp_handle         1    1 0-1
 1057 100142 testpmd             lcore-slave-3         3    1 3

$ cpuset -l 1,2,3 ./build/app/testpmd -l 2,3 --no-huge --no-pci -m 512 \
 -- -i --total-num-mbufs=2048

$ procstat -S 1061
  PID    TID COMM                TDNAME              CPU CSID CPU MASK
 1061 100131 testpmd             -                     2    2 2
 1061 100144 testpmd             eal-intr-thread       1    2 1
 1061 100145 testpmd             rte_mp_handle         1    2 1
 1061 100147 testpmd             lcore-slave-3         3    2 3

$ cpuset -l 2,3 ./build/app/testpmd -l 2,3 --no-huge --no-pci -m 512 \
 -- -i --total-num-mbufs=2048

$ procstat -S 1065
  PID    TID COMM                TDNAME              CPU CSID CPU MASK
 1065 100131 testpmd             -                     2    2 2
 1065 100148 testpmd             eal-intr-thread       2    2 2
 1065 100149 testpmd             rte_mp_handle         2    2 2
 1065 100150 testpmd             lcore-slave-3         3    2 3

Fixes: d651ee4919cd ("eal: set affinity for control threads")

Signed-off-by: David Marchand <david.marchand@redhat.com>
Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
Reviewed-by: Olivier Matz <olivier.matz@6wind.com>
---
 .../prog_guide/env_abstraction_layer.rst      | 22 +++++++++++++++
 lib/librte_eal/common/eal_common_options.c    | 28 +++++++++++++++++++
 lib/librte_eal/common/eal_common_thread.c     | 21 +++-----------
 lib/librte_eal/common/eal_internal_cfg.h      |  3 ++
 lib/librte_eal/common/include/rte_lcore.h     | 17 ++++++++---
 5 files changed, 70 insertions(+), 21 deletions(-)

diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst b/doc/guides/prog_guide/env_abstraction_layer.rst
index 426acfc28..888ce7801 100644
--- a/doc/guides/prog_guide/env_abstraction_layer.rst
+++ b/doc/guides/prog_guide/env_abstraction_layer.rst
@@ -442,4 +442,26 @@ Those TLS include *_cpuset* and *_socket_id*:
 
 
+Control Thread API
+~~~~~~~~~~~~~~~~~~
+
+It is possible to create Control Threads using the public API
+``rte_ctrl_thread_create()``.
+Those threads can be used for management/infrastructure tasks and are used
+internally by DPDK for multi process support and interrupt handling.
+
+Those threads will be scheduled on CPUs part of the original process CPU
+affinity from which the dataplane and service lcores are excluded.
+
+For example, on a 8 CPUs system, starting a dpdk application with -l 2,3
+(dataplane cores), then depending on the affinity configuration which can be
+controlled with tools like taskset (Linux) or cpuset (FreeBSD),
+
+- with no affinity configuration, the Control Threads will end up on
+  0-1,4-7 CPUs.
+- with affinity restricted to 2-4, the Control Threads will end up on
+  CPU 4.
+- with affinity restricted to 2-3, the Control Threads will end up on
+  CPU 2 (master lcore, which is the default when no CPU is available).
+
 .. _known_issue_label:
 
diff --git a/lib/librte_eal/common/eal_common_options.c b/lib/librte_eal/common/eal_common_options.c
index fb966780f..7ba1c449b 100644
--- a/lib/librte_eal/common/eal_common_options.c
+++ b/lib/librte_eal/common/eal_common_options.c
@@ -217,4 +217,5 @@ eal_reset_internal_config(struct internal_config *internal_cfg)
 	internal_cfg->iova_mode = RTE_IOVA_DC;
 	internal_cfg->user_mbuf_pool_ops_name = NULL;
+	CPU_ZERO(&internal_cfg->ctrl_cpuset);
 	internal_cfg->init_complete = 0;
 }
@@ -1359,4 +1360,29 @@ eal_auto_detect_cores(struct rte_config *cfg)
 }
 
+static void
+compute_ctrl_threads_cpuset(struct internal_config *internal_cfg)
+{
+	rte_cpuset_t *cpuset = &internal_cfg->ctrl_cpuset;
+	rte_cpuset_t default_set;
+	unsigned int lcore_id;
+
+	for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
+		if (eal_cpu_detected(lcore_id) &&
+				rte_lcore_has_role(lcore_id, ROLE_OFF)) {
+			CPU_SET(lcore_id, cpuset);
+		}
+	}
+
+	if (pthread_getaffinity_np(pthread_self(), sizeof(rte_cpuset_t),
+				&default_set))
+		CPU_ZERO(&default_set);
+
+	RTE_CPU_AND(cpuset, cpuset, &default_set);
+
+	/* if no detected CPU is off, use master core */
+	if (!CPU_COUNT(cpuset))
+		CPU_SET(rte_get_master_lcore(), cpuset);
+}
+
 int
 eal_cleanup_config(struct internal_config *internal_cfg)
@@ -1392,4 +1418,6 @@ eal_adjust_config(struct internal_config *internal_cfg)
 	}
 
+	compute_ctrl_threads_cpuset(internal_cfg);
+
 	/* if no memory amounts were requested, this will result in 0 and
 	 * will be overridden later, right after eal_hugepage_info_init() */
diff --git a/lib/librte_eal/common/eal_common_thread.c b/lib/librte_eal/common/eal_common_thread.c
index a3985ce86..14f206c04 100644
--- a/lib/librte_eal/common/eal_common_thread.c
+++ b/lib/librte_eal/common/eal_common_thread.c
@@ -17,4 +17,5 @@
 #include <rte_log.h>
 
+#include "eal_internal_cfg.h"
 #include "eal_private.h"
 #include "eal_thread.h"
@@ -169,8 +170,7 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
 		void *(*start_routine)(void *), void *arg)
 {
+	rte_cpuset_t *cpuset = &internal_config.ctrl_cpuset;
 	struct rte_thread_ctrl_params *params;
-	unsigned int lcore_id;
-	rte_cpuset_t cpuset;
-	int cpu_found, ret;
+	int ret;
 
 	params = malloc(sizeof(*params));
@@ -196,18 +196,5 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
 	}
 
-	cpu_found = 0;
-	CPU_ZERO(&cpuset);
-	for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
-		if (eal_cpu_detected(lcore_id) &&
-				rte_lcore_has_role(lcore_id, ROLE_OFF)) {
-			CPU_SET(lcore_id, &cpuset);
-			cpu_found = 1;
-		}
-	}
-	/* if no detected cpu is off, use master core */
-	if (!cpu_found)
-		CPU_SET(rte_get_master_lcore(), &cpuset);
-
-	ret = pthread_setaffinity_np(*thread, sizeof(cpuset), &cpuset);
+	ret = pthread_setaffinity_np(*thread, sizeof(*cpuset), cpuset);
 	if (ret)
 		goto fail;
diff --git a/lib/librte_eal/common/eal_internal_cfg.h b/lib/librte_eal/common/eal_internal_cfg.h
index 783ce7de8..189d4f5b2 100644
--- a/lib/librte_eal/common/eal_internal_cfg.h
+++ b/lib/librte_eal/common/eal_internal_cfg.h
@@ -14,4 +14,6 @@
 #include <rte_pci_dev_feature_defs.h>
 
+#include "eal_thread.h"
+
 #define MAX_HUGEPAGE_SIZES 3  /**< support up to 3 page sizes */
 
@@ -72,4 +74,5 @@ struct internal_config {
 	struct hugepage_info hugepage_info[MAX_HUGEPAGE_SIZES];
 	enum rte_iova_mode iova_mode ;    /**< Set IOVA mode on this system  */
+	rte_cpuset_t ctrl_cpuset;         /**< cpuset for ctrl threads */
 	volatile unsigned int init_complete;
 	/**< indicates whether EAL has completed initialization */
diff --git a/lib/librte_eal/common/include/rte_lcore.h b/lib/librte_eal/common/include/rte_lcore.h
index 6e09d9181..dea17f500 100644
--- a/lib/librte_eal/common/include/rte_lcore.h
+++ b/lib/librte_eal/common/include/rte_lcore.h
@@ -24,8 +24,16 @@ extern "C" {
 
 #if defined(__linux__)
-	typedef	cpu_set_t rte_cpuset_t;
+typedef	cpu_set_t rte_cpuset_t;
+#define RTE_CPU_AND(dst, src1, src2) CPU_AND(dst, src1, src2)
 #elif defined(__FreeBSD__)
 #include <pthread_np.h>
-	typedef cpuset_t rte_cpuset_t;
+typedef cpuset_t rte_cpuset_t;
+#define RTE_CPU_AND(dst, src1, src2) do \
+{ \
+	cpuset_t tmp; \
+	CPU_COPY(src1, &tmp); \
+	CPU_AND(&tmp, src2); \
+	CPU_COPY(&tmp, dst); \
+} while (0)
 #endif
 
@@ -281,6 +289,7 @@ int rte_thread_setname(pthread_t id, const char *name);
  *
  * Wrapper to pthread_create(), pthread_setname_np() and
- * pthread_setaffinity_np(). The dataplane and service lcores are
- * excluded from the affinity of the new thread.
+ * pthread_setaffinity_np(). The affinity of the new thread is based
+ * on the CPU affinity retrieved at the time rte_eal_init() was called,
+ * the dataplane and service lcores are then excluded.
  *
  * @param thread
-- 
2.20.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2019-04-10 14:06:11.726379211 +0100
+++ 0050-eal-restrict-control-threads-to-startup-CPU-affinity.patch	2019-04-10 14:06:07.997291198 +0100
@@ -1,8 +1,10 @@
-From c3568ea376700df061abcbeabc40ddaed7841e1a Mon Sep 17 00:00:00 2001
+From 23a9f69ed3d9c98b1912df305552ed6dbc639e8f Mon Sep 17 00:00:00 2001
 From: David Marchand <david.marchand@redhat.com>
 Date: Tue, 19 Feb 2019 21:41:11 +0100
 Subject: [PATCH] eal: restrict control threads to startup CPU affinity
 
+[ upstream commit c3568ea376700df061abcbeabc40ddaed7841e1a ]
+
 Spawning the ctrl threads on anything that is not part of the eal
 coremask is not that polite to the rest of the system, especially
 when you took good care to pin your processes on cpu resources with
@@ -52,7 +54,6 @@
  1065 100150 testpmd             lcore-slave-3         3    2 3
 
 Fixes: d651ee4919cd ("eal: set affinity for control threads")
-Cc: stable@dpdk.org
 
 Signed-off-by: David Marchand <david.marchand@redhat.com>
 Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
@@ -66,10 +67,10 @@
  5 files changed, 70 insertions(+), 21 deletions(-)
 
 diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst b/doc/guides/prog_guide/env_abstraction_layer.rst
-index 929d76dba..67b45ba7d 100644
+index 426acfc28..888ce7801 100644
 --- a/doc/guides/prog_guide/env_abstraction_layer.rst
 +++ b/doc/guides/prog_guide/env_abstraction_layer.rst
-@@ -499,4 +499,26 @@ Those TLS include *_cpuset* and *_socket_id*:
+@@ -442,4 +442,26 @@ Those TLS include *_cpuset* and *_socket_id*:
  
  
 +Control Thread API
@@ -97,16 +98,16 @@
  .. _known_issue_label:
  
 diff --git a/lib/librte_eal/common/eal_common_options.c b/lib/librte_eal/common/eal_common_options.c
-index 1f45f82f3..9e61ee436 100644
+index fb966780f..7ba1c449b 100644
 --- a/lib/librte_eal/common/eal_common_options.c
 +++ b/lib/librte_eal/common/eal_common_options.c
-@@ -218,4 +218,5 @@ eal_reset_internal_config(struct internal_config *internal_cfg)
+@@ -217,4 +217,5 @@ eal_reset_internal_config(struct internal_config *internal_cfg)
  	internal_cfg->iova_mode = RTE_IOVA_DC;
  	internal_cfg->user_mbuf_pool_ops_name = NULL;
 +	CPU_ZERO(&internal_cfg->ctrl_cpuset);
  	internal_cfg->init_complete = 0;
  }
-@@ -1360,4 +1361,29 @@ eal_auto_detect_cores(struct rte_config *cfg)
+@@ -1359,4 +1360,29 @@ eal_auto_detect_cores(struct rte_config *cfg)
  }
  
 +static void
@@ -136,7 +137,7 @@
 +
  int
  eal_cleanup_config(struct internal_config *internal_cfg)
-@@ -1393,4 +1419,6 @@ eal_adjust_config(struct internal_config *internal_cfg)
+@@ -1392,4 +1418,6 @@ eal_adjust_config(struct internal_config *internal_cfg)
  	}
  
 +	compute_ctrl_threads_cpuset(internal_cfg);
@@ -185,7 +186,7 @@
  	if (ret)
  		goto fail;
 diff --git a/lib/librte_eal/common/eal_internal_cfg.h b/lib/librte_eal/common/eal_internal_cfg.h
-index 60eaead8f..edff09d07 100644
+index 783ce7de8..189d4f5b2 100644
 --- a/lib/librte_eal/common/eal_internal_cfg.h
 +++ b/lib/librte_eal/common/eal_internal_cfg.h
 @@ -14,4 +14,6 @@
@@ -195,7 +196,7 @@
 +
  #define MAX_HUGEPAGE_SIZES 3  /**< support up to 3 page sizes */
  
-@@ -74,4 +76,5 @@ struct internal_config {
+@@ -72,4 +74,5 @@ struct internal_config {
  	struct hugepage_info hugepage_info[MAX_HUGEPAGE_SIZES];
  	enum rte_iova_mode iova_mode ;    /**< Set IOVA mode on this system  */
 +	rte_cpuset_t ctrl_cpuset;         /**< cpuset for ctrl threads */