Hi Norman,
Yes, I got the L4 headers to work now.
What if one program would create multiple CPU sessions and specify the CPU session for each thread as constructor argument of the 'Thread' class? In the extreme case, each thread could be created via a distinct CPU session using a different affinity. The program would express its desired affinity for each CPU session as session argument. The parent then has the option to change the affinity when forwarding the session request towards Genode's core. This would be a quite powerful mechanism to assign any subsystem to arbitrary sets of CPUs without letting the subsystem know about it.
Yes I think this would work.
Daniel
On 03/17/2011 11:42 AM, Norman Feske wrote:
Hi Daniel,
As far as design choice, I think you need both. When you can use an affinity mask for a set of threads that belong to a single CPU session, then setting this mask through the CPU session works. However, lets say you want to explicitly define each individual mapping of thread to core. In this case you either need to be able to define the affinity from the thread, or some how build a map of threads-to-affinity in the CPU session. The latter could be cleaner, but less conventional.
What if one program would create multiple CPU sessions and specify the CPU session for each thread as constructor argument of the 'Thread' class? In the extreme case, each thread could be created via a distinct CPU session using a different affinity. The program would express its desired affinity for each CPU session as session argument. The parent then has the option to change the affinity when forwarding the session request towards Genode's core. This would be a quite powerful mechanism to assign any subsystem to arbitrary sets of CPUs without letting the subsystem know about it.
Currently, the 'Thread_base' implementation always uses the CPU session of 'Genode::env()->cpu_session()'. However, the replacement of this hard-wired policy by a construction argument would be a sensible way to enable the binding of threads to manually created CPU sessions.
I did try to include the l4sys headers in my genode program, but it sort of blew up - it found the headers but not things like L4_PAGESHIFT.
Normally, this shouldn't be a problem. Can you give the following program a try?
base-foc/src/test/headers/test.cc:
namespace Fiasco { #include<l4/sys/types.h> }
#include<base/printf.h>
int main(int argc, char **argv) { using namespace Fiasco;
Genode::printf("L4_PAGESHIFT=%ld\n", (long)L4_PAGESHIFT); return 0;}
base-foc/src/test/headers/target.mk:
TARGET = test-headers SRC_CC = test.cc LIBS = env cxx
base-foc/run/headers.run:
build "core init test/headers" create_boot_directory
install_config { <config> <parent-provides> <service name="ROM"/> <service name="LOG"/> </parent-provides> <default-route> <any-service> <parent/> </any-service> </default-route> <start name="test-headers"> <resource name="RAM" quantum="1M"/> </start> </config> }
build_boot_image "core init test-headers" append qemu_args "-nographic -m 64" run_genode_until "exited with exit value 0" 20
To execute the test, just issue 'make run/headers' from your build directory.
Cheers Norman