Hi, I'm planning on building a small example of a producer/consumer build on top of L4Re. From the documentation I know about the shared memory inteface which will help to pass information from the producer to the consumer but I am a bit clueless on how I notify the consumer that there is something new to read. The semaphore is only to be used in between threads so there is no way to use them for IPC between Tasks?! Is there another possibility to make this work other than to use polling? regards Tobi
On 12.06.2012 14:41, Tobias Fink wrote:
Hi,
I'm planning on building a small example of a producer/consumer build on top of L4Re. From the documentation I know about the shared memory inteface which will help to pass information from the producer to the consumer but I am a bit clueless on how I notify the consumer that there is something new to read. The semaphore is only to be used in between threads so there is no way to use them for IPC between Tasks?! Is there another possibility to make this work other than to use polling?
There is no communication between tasks, because tasks in terms of L4 / Fiasco.OC are only address spaces (plus some other state, such as the capability index table). The units of execution are always threads and hence communication always happens between those. Does that help you? Bjoern -- Dipl.-Inf. Bjoern Doebel Mail: doebel@tudos.org TU Dresden, OS Chair Phone: +49 351 463 38 799 Noethnitzer Str. 46 Fax: +49 351 463 38 284 01187 Dresden, Germany WWW: http://www.tudos.org/~doebel -- "Futbol no es en simple juego. Es una arma de la revolucion!"
Hi Björn, that helps to understand it a lot yes. The background of this is, that I want to show what low level communication possibilities there would be for two instances of l4linux for example without having to use sockets or similar technologies. If this would be in principle possible due to the fact that everything is a thread, then the example that Vasily linked to is enough for me. Thank you! Tobi 2012/6/12 Björn Döbel <doebel@os.inf.tu-dresden.de>:
On 12.06.2012 14:41, Tobias Fink wrote:
Hi,
I'm planning on building a small example of a producer/consumer build on top of L4Re. From the documentation I know about the shared memory inteface which will help to pass information from the producer to the consumer but I am a bit clueless on how I notify the consumer that there is something new to read. The semaphore is only to be used in between threads so there is no way to use them for IPC between Tasks?! Is there another possibility to make this work other than to use polling?
There is no communication between tasks, because tasks in terms of L4 / Fiasco.OC are only address spaces (plus some other state, such as the capability index table). The units of execution are always threads and hence communication always happens between those. Does that help you?
Bjoern -- Dipl.-Inf. Bjoern Doebel Mail: doebel@tudos.org TU Dresden, OS Chair Phone: +49 351 463 38 799 Noethnitzer Str. 46 Fax: +49 351 463 38 284 01187 Dresden, Germany WWW: http://www.tudos.org/~doebel -- "Futbol no es en simple juego. Es una arma de la revolucion!"
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Right now I'm examining the example included in L4Re: http://os.inf.tu-dresden.de/L4Re/doc/examples_2libs_2shmc_2prodcons_8c-examp... This exists at this point: if (l4shmc_create("testshm", 8192)) return 1; I'm testing on an IGEPv2 Board with a DM3730 ARM Cortex-A8 processor. What am I missing? Here is the output from the Boot process: SIGMA0: Hello! KIP @ 80002000 allocated 4KB for maintenance structures SIGMA0: Dump of all resource maps RAM:------------------------ [0:80000000;80000fff] [0:8005d000;8008ffff] [0:8009f000;8013ffff] [4:80140000;80171fff] [0:80172000;80177fff] [4:80178000;8018efff] [0:8018f000;8100efff] [4:8100f000;8100ffff] [0:81010000;8118ffff] [4:81190000;8134afff] [0:8134b000;86ffffff] IOMEM:---------------------- [0:0;7fffffff] [0:88000000;ffffffff] MOE: Hello world MOE: found 112192 KByte free memory MOE: found RAM from 80000000 to 87000000 MOE: allocated 112 KByte for the page array @0x8005d000 MOE: virtual user address space [0-bfffffff] MOE: rom name space cap -> [C:501000] 2012/6/12 Tobias Fink <tobias.fink@stud.h-da.de>:
Hi Björn,
that helps to understand it a lot yes. The background of this is, that I want to show what low level communication possibilities there would be for two instances of l4linux for example without having to use sockets or similar technologies. If this would be in principle possible due to the fact that everything is a thread, then the example that Vasily linked to is enough for me. Thank you!
Tobi
2012/6/12 Björn Döbel <doebel@os.inf.tu-dresden.de>:
On 12.06.2012 14:41, Tobias Fink wrote:
Hi,
I'm planning on building a small example of a producer/consumer build on top of L4Re. From the documentation I know about the shared memory inteface which will help to pass information from the producer to the consumer but I am a bit clueless on how I notify the consumer that there is something new to read. The semaphore is only to be used in between threads so there is no way to use them for IPC between Tasks?! Is there another possibility to make this work other than to use polling?
There is no communication between tasks, because tasks in terms of L4 / Fiasco.OC are only address spaces (plus some other state, such as the capability index table). The units of execution are always threads and hence communication always happens between those. Does that help you?
Bjoern -- Dipl.-Inf. Bjoern Doebel Mail: doebel@tudos.org TU Dresden, OS Chair Phone: +49 351 463 38 799 Noethnitzer Str. 46 Fax: +49 351 463 38 284 01187 Dresden, Germany WWW: http://www.tudos.org/~doebel -- "Futbol no es en simple juego. Es una arma de la revolucion!"
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You need to add in LUA file communication channel: http://os.inf.tu-dresden.de/L4Re/doc/examples_2libs_2l4re_2c_09_09_2shared_d... 13.06.2012, в 18:13, Tobias Fink <tobias.fink@stud.h-da.de> написал(а):
Right now I'm examining the example included in L4Re: http://os.inf.tu-dresden.de/L4Re/doc/examples_2libs_2shmc_2prodcons_8c-examp... This exists at this point:
if (l4shmc_create("testshm", 8192)) return 1;
I'm testing on an IGEPv2 Board with a DM3730 ARM Cortex-A8 processor. What am I missing?
Here is the output from the Boot process:
SIGMA0: Hello! KIP @ 80002000 allocated 4KB for maintenance structures SIGMA0: Dump of all resource maps RAM:------------------------ [0:80000000;80000fff] [0:8005d000;8008ffff] [0:8009f000;8013ffff] [4:80140000;80171fff] [0:80172000;80177fff] [4:80178000;8018efff] [0:8018f000;8100efff] [4:8100f000;8100ffff] [0:81010000;8118ffff] [4:81190000;8134afff] [0:8134b000;86ffffff] IOMEM:---------------------- [0:0;7fffffff] [0:88000000;ffffffff] MOE: Hello world MOE: found 112192 KByte free memory MOE: found RAM from 80000000 to 87000000 MOE: allocated 112 KByte for the page array @0x8005d000 MOE: virtual user address space [0-bfffffff] MOE: rom name space cap -> [C:501000]
2012/6/12 Tobias Fink <tobias.fink@stud.h-da.de>:
Hi Björn,
that helps to understand it a lot yes. The background of this is, that I want to show what low level communication possibilities there would be for two instances of l4linux for example without having to use sockets or similar technologies. If this would be in principle possible due to the fact that everything is a thread, then the example that Vasily linked to is enough for me. Thank you!
Tobi
2012/6/12 Björn Döbel <doebel@os.inf.tu-dresden.de>:
On 12.06.2012 14:41, Tobias Fink wrote:
Hi,
I'm planning on building a small example of a producer/consumer build on top of L4Re. From the documentation I know about the shared memory inteface which will help to pass information from the producer to the consumer but I am a bit clueless on how I notify the consumer that there is something new to read. The semaphore is only to be used in between threads so there is no way to use them for IPC between Tasks?! Is there another possibility to make this work other than to use polling?
There is no communication between tasks, because tasks in terms of L4 / Fiasco.OC are only address spaces (plus some other state, such as the capability index table). The units of execution are always threads and hence communication always happens between those. Does that help you?
Bjoern -- Dipl.-Inf. Bjoern Doebel Mail: doebel@tudos.org TU Dresden, OS Chair Phone: +49 351 463 38 799 Noethnitzer Str. 46 Fax: +49 351 463 38 284 01187 Dresden, Germany WWW: http://www.tudos.org/~doebel -- "Futbol no es en simple juego. Es una arma de la revolucion!"
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Hi, thank you for your quick answer 2012/6/13 Sartakov A. Vasily <sartakov@ksyslabs.org>:
You need to add in LUA file communication channel:
http://os.inf.tu-dresden.de/L4Re/doc/examples_2libs_2l4re_2c_09_09_2shared_d...
That works for the shared_ds example but I as I tried to get the prodcons example to work it still fails. This is the Lua-Script I was using: -- Include L4 functionality require("L4"); -- Create a channel from the client to the server local channel = L4.default_loader:new_channel(); L4.default_loader:start( { caps = { shm = channel:svr() }, log = { "shmc", "yellow" } }, "rom/ex_shmc" );
Hello Tobias, maybe try something like this: -- Include L4 functionality require("L4"); local l = L4.default_loader; local nsshm = l:create_namespace({}); L4.default_loader:start( { caps = { testshm = nsshm:m("rws") }, log = { "shmc", "yellow" } }, "rom/ex_shmc" ); Micha On 06/14/2012 11:30 AM, Tobias Fink wrote:
Hi,
thank you for your quick answer
2012/6/13 Sartakov A. Vasily<sartakov@ksyslabs.org>:
You need to add in LUA file communication channel:
http://os.inf.tu-dresden.de/L4Re/doc/examples_2libs_2l4re_2c_09_09_2shared_d... That works for the shared_ds example but I as I tried to get the prodcons example to work it still fails. This is the Lua-Script I was using:
-- Include L4 functionality require("L4");
-- Create a channel from the client to the server local channel = L4.default_loader:new_channel();
L4.default_loader:start( { caps = { shm = channel:svr() }, log = { "shmc", "yellow" } }, "rom/ex_shmc" );
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Hey Micha, thank you very much, that did the trick. Where can I find more documentation about the Lua classes used for L4Re. I only can find examples and not a conclusive documentation? Tobi
participants (4)
-
Björn Döbel -
Michael Jahn -
Sartakov A. Vasily -
Tobias Fink