* Re: [RFC PATCH] make SMP option only use online cpus (cyclictest)
2014-08-14 17:29 [RFC PATCH] make SMP option only use online cpus (cyclictest) Joakim Hernberg
@ 2014-08-15 12:54 ` John Kacur
0 siblings, 0 replies; 2+ messages in thread
From: John Kacur @ 2014-08-15 12:54 UTC (permalink / raw)
To: Joakim Hernberg; +Cc: linux-rt-users, Clark Williams, John Kacur
On Thu, 14 Aug 2014, Joakim Hernberg wrote:
> When I boot my 8 core i7 laptop with the maxcpus=4 kernel boot flag,
> cyclictest -S runs 8 threads. This patch makes it only use the online
> cpus instead.
>
> diff --git a/src/cyclictest/cyclictest.c
> b/src/cyclictest/cyclictest.c index 4547831..92fc346 100644
> --- a/src/cyclictest/cyclictest.c
> +++ b/src/cyclictest/cyclictest.c
> @@ -1740,7 +1740,7 @@ int main(int argc, char **argv)
> sigset_t sigset;
> int signum = SIGALRM;
> int mode;
> - int max_cpus = sysconf(_SC_NPROCESSORS_CONF);
> + int max_cpus = sysconf(_SC_NPROCESSORS_ONLN);
> int i, ret = -1;
> int status;
>
> diff --git a/src/cyclictest/rt_numa.h b/src/cyclictest/rt_numa.h
> index e64c446..c2b3e85 100644
> --- a/src/cyclictest/rt_numa.h
> +++ b/src/cyclictest/rt_numa.h
> @@ -128,7 +128,7 @@ static int rt_numa_numa_node_of_cpu(int cpu)
> int max_node, max_cpus;
>
> max_node = numa_max_node();
> - max_cpus = sysconf(_SC_NPROCESSORS_CONF);
> + max_cpus = sysconf(_SC_NPROCESSORS_ONLN);
>
> if (cpu > max_cpus) {
> errno = EINVAL;
>
> --
This is fine, in anycase, it's not less robust than what we are currently
doing. (I suppose we really should be checking the result of sysconf)
I changed the description a little bit.
Clark, I pushed the following version to my repo, please pull
>From 863f1482220034de0a85f8150384931318325953 Mon Sep 17 00:00:00 2001
From: Joakim Hernberg <jbh@alchemy.lu>
Date: Thu, 14 Aug 2014 19:29:29 +0200
Subject: [PATCH] cyclictest: make affinity option only use number of online
cpus
When I boot my 8 core i7 laptop with the maxcpus=4 kernel boot flag,
cyclictest -S runs 8 threads. This patch makes it only use the number
of online cpus instead.
Signed-off-by: Joakim Hernberg <jhernberg@alchemy.lu>
Signed-off-by: John Kacur <jkacur@redhat.com>
---
src/cyclictest/cyclictest.c | 2 +-
src/cyclictest/rt_numa.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index a3e7b1d6c377..c727d54364b1 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -1763,7 +1763,7 @@ int main(int argc, char **argv)
sigset_t sigset;
int signum = SIGALRM;
int mode;
- int max_cpus = sysconf(_SC_NPROCESSORS_CONF);
+ int max_cpus = sysconf(_SC_NPROCESSORS_ONLN);
int i, ret = -1;
int status;
diff --git a/src/cyclictest/rt_numa.h b/src/cyclictest/rt_numa.h
index 60a143721da1..06c9420e53cc 100644
--- a/src/cyclictest/rt_numa.h
+++ b/src/cyclictest/rt_numa.h
@@ -128,7 +128,7 @@ static int rt_numa_numa_node_of_cpu(int cpu)
int max_node, max_cpus;
max_node = numa_max_node();
- max_cpus = sysconf(_SC_NPROCESSORS_CONF);
+ max_cpus = sysconf(_SC_NPROCESSORS_ONLN);
if (cpu > max_cpus) {
errno = EINVAL;
--
1.8.1.4
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