On a numa system we allocate a stack from the closest NUMA node
for each measurement thread. We need to touch those stack pages
to prevent them faulting when first run. Not a big deal on a
system with just a few cores, but overhead adds up with 32+ cores.
Signed-off-by: Clark Williams <williams@xxxxxxxxxx>
---
src/cyclictest/cyclictest.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index 5e23fc58f602..49a81f168cdb 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -2376,6 +2376,9 @@ int main(int argc, char **argv)
/* allocate memory for a stack on appropriate node */
stack = rt_numa_numa_alloc_onnode(stksize, node, i);
+ /* touch the stack pages to pre-fault them in */
+ memset(stack, 0, stksize);
+
/* set the thread's stack */
if (pthread_attr_setstack(&attr, stack, stksize))
fatal("failed to set stack addr for thread %d to 0x%x\n",
--
2.9.3
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