[dpdk-dev] [PATCH v2] eal: add ticket based reader writer lock

[Stephen Hemminger]

This patch implements a reader/writer ticket lock because the
current DPDK reader/writer lock will starve writers when
presented with a stream of readers.

This lock type acts like rte_rwlock() but uses a ticket algorithm
and is therefore fair for multiple writers and readers. It acts
like the existing DPDK ticket and MCS lock but supports
reader/writer semantics.

It is referred to as "Simple, non-scalable, fair reader-writer lock"
in the MCS paper from PPoP '91.

The tests are just a clone of existing rte_rwlock with test
and function names changed. So the new ticket rwlocks should be drop
in replacement for most users.

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
v2 - fix a minor checkpatch warning and docbook param error

 app/test/autotest_data.py              | 6 ++++++
 app/test/meson.build                   | 5 +++++
 doc/api/doxy-api-index.md              | 1 +
 lib/librte_eal/arm/include/meson.build | 1 +
 lib/librte_eal/include/meson.build     | 1 +
 lib/librte_eal/ppc/include/meson.build | 1 +
 lib/librte_eal/x86/include/meson.build | 1 +
 7 files changed, 16 insertions(+)

diff --git a/app/test/autotest_data.py b/app/test/autotest_data.py
index 097638941f19..62816c36d873 100644
--- a/app/test/autotest_data.py
+++ b/app/test/autotest_data.py
@@ -231,6 +231,12 @@
         "Func":    ticketlock_autotest,
         "Report":  None,
     },
+    {
+        "Name":    "Ticket rwlock autotest",
+        "Command": "ticket_rwlock_autotest",
+        "Func":    ticketrwlock_autotest,
+        "Report":  None,
+    },
     {
         "Name":    "MCSlock autotest",
         "Command": "mcslock_autotest",
diff --git a/app/test/meson.build b/app/test/meson.build
index 0889ad4c2367..e6ace8e597e6 100644
--- a/app/test/meson.build
+++ b/app/test/meson.build
@@ -136,6 +136,7 @@ test_sources = files('commands.c',
 	'test_timer_racecond.c',
 	'test_timer_secondary.c',
 	'test_ticketlock.c',
+	'test_ticket_rwlock.c',
 	'test_trace.c',
 	'test_trace_register.c',
 	'test_trace_perf.c',
@@ -247,6 +248,10 @@ fast_tests = [
         ['table_autotest', true],
         ['tailq_autotest', true],
         ['ticketlock_autotest', true],
+        ['ticketrwlock_test1_autotest', true],
+        ['ticketrwlock_rda_autotest', true],
+        ['ticketrwlock_rds_wrm_autotest', true],
+        ['ticketrwlock_rde_wro_autotest', true],
         ['timer_autotest', false],
         ['user_delay_us', true],
         ['version_autotest', true],
diff --git a/doc/api/doxy-api-index.md b/doc/api/doxy-api-index.md
index 748514e24316..d76a4c8ba1c4 100644
--- a/doc/api/doxy-api-index.md
+++ b/doc/api/doxy-api-index.md
@@ -76,6 +76,7 @@ The public API headers are grouped by topics:
   [rwlock]             (@ref rte_rwlock.h),
   [spinlock]           (@ref rte_spinlock.h),
   [ticketlock]         (@ref rte_ticketlock.h),
+  [ticketrwlock]       (@ref rte_ticket_rwlock.h),
   [RCU]                (@ref rte_rcu_qsbr.h)
 
 - **CPU arch**:
diff --git a/lib/librte_eal/arm/include/meson.build b/lib/librte_eal/arm/include/meson.build
index 770766de1a34..951a527ffa64 100644
--- a/lib/librte_eal/arm/include/meson.build
+++ b/lib/librte_eal/arm/include/meson.build
@@ -28,6 +28,7 @@ arch_headers = files(
 	'rte_rwlock.h',
 	'rte_spinlock.h',
 	'rte_ticketlock.h',
+	'rte_ticket_rwlock.h',
 	'rte_vect.h',
 )
 install_headers(arch_headers, subdir: get_option('include_subdir_arch'))
diff --git a/lib/librte_eal/include/meson.build b/lib/librte_eal/include/meson.build
index 0dea342e1deb..fe5c19748926 100644
--- a/lib/librte_eal/include/meson.build
+++ b/lib/librte_eal/include/meson.build
@@ -65,6 +65,7 @@ generic_headers = files(
 	'generic/rte_rwlock.h',
 	'generic/rte_spinlock.h',
 	'generic/rte_ticketlock.h',
+	'generic/rte_ticket_rwlock.h',
 	'generic/rte_vect.h',
 )
 install_headers(generic_headers, subdir: 'generic')
diff --git a/lib/librte_eal/ppc/include/meson.build b/lib/librte_eal/ppc/include/meson.build
index dae40ede546e..0bc560327749 100644
--- a/lib/librte_eal/ppc/include/meson.build
+++ b/lib/librte_eal/ppc/include/meson.build
@@ -16,6 +16,7 @@ arch_headers = files(
 	'rte_rwlock.h',
 	'rte_spinlock.h',
 	'rte_ticketlock.h',
+	'rte_ticket_rwlock.h',
 	'rte_vect.h',
 )
 install_headers(arch_headers, subdir: get_option('include_subdir_arch'))
diff --git a/lib/librte_eal/x86/include/meson.build b/lib/librte_eal/x86/include/meson.build
index 549cc21a42ed..e9169f0d1da5 100644
--- a/lib/librte_eal/x86/include/meson.build
+++ b/lib/librte_eal/x86/include/meson.build
@@ -20,6 +20,7 @@ arch_headers = files(
 	'rte_rwlock.h',
 	'rte_spinlock.h',
 	'rte_ticketlock.h',
+	'rte_ticket_rwlock.h',
 	'rte_vect.h',
 )
 install_headers(arch_headers, subdir: get_option('include_subdir_arch'))
-- 
2.29.2