- Original Message -
From: Simon Marchi simon.mar...@polymtl.ca
To: lttng-dev@lists.lttng.org
Sent: Friday, December 6, 2013 10:17:55 PM
Subject: [lttng-dev] [PATCH userspace-rcu] Set RCU_HAVE_FENCE to false on
Intel Xeon Phi
It currently fails to compile, because the Phi does not have fence
instructions.
It will use lock prefixed instructions for all memory barriers, which
is overkill for this platform, but at least it will work.
Merged. It's overkill, but at least it will compile. We'll see if we
want to improve the memory barriers and make them cheaper as an
optimization.
Thanks,
Mathieu
Signed-off-by: Simon Marchi simon.mar...@polymtl.ca
---
configure.ac |5 -
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/configure.ac b/configure.ac
index 774094e..079c145 100644
--- a/configure.ac
+++ b/configure.ac
@@ -140,7 +140,10 @@ AS_IF([test x$ARCHTYPE = xx86],[
#For now, using lock; addl compatibility mode even for i686, because the
#Pentium III is seen as a i686, but lacks mfence instruction.
#Only using fence for x86_64.
- AS_IF([test x$host_cpu != xi386 -a x$host_cpu != xi486 -a
x$host_cpu != xi586 -a x$host_cpu != xi686],[
+ #
+ #k1om is the name for the Intel MIC family (Xeon Phi). It is an x86_64
+ #variant but lacks fence instructions.
+ AS_IF([test x$host_cpu != xi386 -a x$host_cpu != xi486 -a
x$host_cpu != xi586 -a x$host_cpu != xi686 -a x$host_vendor !=
xk1om],[
AC_MSG_RESULT([yes])
AC_DEFINE([CONFIG_RCU_HAVE_FENCE], [1])
],[
--
1.7.1
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--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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