[Xenomai] [PATCH] cobalt: increase default system heap size

[Xenomai] [PATCH] cobalt: increase default system heap size

[Dmitriy Cherkasov]

On arm64, running the included switchtest program hits the default 
system heap limit of 256k.

The program creates 97 threads, each allocating space on the system heap 
for struct cobalt_thread (3616 bytes on arm64). This adds up to a total 
of 350725 bytes required.

This patch increases the default system heap size to 512k.

---
  kernel/cobalt/Kconfig | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/cobalt/Kconfig b/kernel/cobalt/Kconfig
index afa62d2..24f09e8 100644
--- a/kernel/cobalt/Kconfig
+++ b/kernel/cobalt/Kconfig
@@ -257,7 +257,7 @@ config XENO_OPT_REGISTRY_NRSLOTS

  config XENO_OPT_SYS_HEAPSZ
         int "Size of system heap (Kb)"
-       default 256
+       default 512
         help
         The system heap is used for various internal allocations by
         the Cobalt kernel. The size is expressed in Kilobytes.
-- 
1.9.1

Re: [Xenomai] [PATCH] cobalt: increase default system heap size

[Gilles Chanteperdrix]

On Tue, Dec 01, 2015 at 11:29:05AM -0800, Dmitriy Cherkasov wrote:
> On arm64, running the included switchtest program hits the default 
> system heap limit of 256k.
> 
> The program creates 97 threads, each allocating space on the system heap 
> for struct cobalt_thread (3616 bytes on arm64). This adds up to a total 
> of 350725 bytes required.
> 
> This patch increases the default system heap size to 512k.

The number of threads depends on the number of cpus, so, if a
64 bits octo-core requires simply doubling the size, the patch looks
reasonable. Alternatively, we can keep 256 KiB for the !SMP case,
and simply change the default in the SMP case.

-- 
					    Gilles.
https://click-hack.org