crypto-ipsecmb: fix perf scaling in ipsecmb v1.3

Type: fix

This patch adds a fix for an issue in the ipsecmb library resulting in
lower than expected performance in multi-threaded scenarios. This is
due to multiple threads writing the same global variable simultaneously.

Signed-off-by: marcel.d.cornu@intel.com
Change-Id: Ibcac321aa40da4b1709198dec3e18226e3891138

build/external/patches/ipsec-mb_1.3/0001-Fix-for-perf-scaling-on-release-1.3.patch

@@ -0,0 +1,70 @@
+From 6b941770f0114d42e87875562d5174bc70c5ac65 Mon Sep 17 00:00:00 2001
+From: Pablo de Lara <pablo.de.lara.guarch@intel.com>
+Date: Tue, 6 Dec 2022 10:59:35 +0000
+Subject: [PATCH] Fix for perf scaling on release 1.3
+
+---
+ lib/include/error.h   | 10 +++++++---
+ lib/include/error.inc |  3 +++
+ lib/x86_64/error.c    |  2 +-
+ 3 files changed, 11 insertions(+), 4 deletions(-)
+
+diff --git a/lib/include/error.h b/lib/include/error.h
+index 73d44f51..778df4b1 100644
+--- a/lib/include/error.h
++++ b/lib/include/error.h
+@@ -32,7 +32,7 @@
+  * declare global variable to store
+  * process wide error status
+  */
+-extern int imb_errno;
++extern volatile int imb_errno;
+ 
+ /**
+  * @brief API to set error status
+@@ -47,8 +47,12 @@ void imb_set_errno(IMB_MGR *mb_mgr, const int errnum)
+         if (mb_mgr != NULL)
+                 mb_mgr->imb_errno = errnum;
+ 
+-        /* set global error status */
+-        imb_errno = errnum;
++        /*
++         * set global error status
++         * (only if different, to limit unneeded stores)
++         */
++        if (imb_errno != errnum)
++                imb_errno = errnum;
+ }
+ 
+ #endif /* ERROR_H */
+diff --git a/lib/include/error.inc b/lib/include/error.inc
+index 54df265f..5ea53a59 100644
+--- a/lib/include/error.inc
++++ b/lib/include/error.inc
+@@ -103,7 +103,10 @@ SET_ERRNO_TYPES \
+ ;; Reset global imb_errno to 0
+ %macro IMB_ERR_CHECK_RESET 0
+ 
++        cmp     dword [rel imb_errno], 0
++        jz      %%do_not_reset
+         mov     dword [rel imb_errno], 0
++%%do_not_reset:
+ %endmacro
+ 
+ ;; Set GP reg and global imb_errno to 0
+diff --git a/lib/x86_64/error.c b/lib/x86_64/error.c
+index 19189093..24dcded3 100644
+--- a/lib/x86_64/error.c
++++ b/lib/x86_64/error.c
+@@ -39,7 +39,7 @@
+ #pragma warning(disable : 4996)
+ #endif
+ 
+-IMB_DLL_LOCAL int imb_errno;
++IMB_DLL_LOCAL volatile int imb_errno;
+ IMB_DLL_LOCAL const int imb_errno_types[] = {
+         IMB_ERR_NULL_MBMGR,
+         IMB_ERR_JOB_NULL_SRC,
+-- 
+2.34.1
+