SPE to SPE signaling

From Cellbe

(Difference between revisions)
(→Version 3.0 Issues)
(→SPE side: sender)
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}
}
</pre>
</pre>
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==SPE side: sender==
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It makes me sad that my immediate rietcaon is to think of the flaws in the author's arguments, because this is the sort of article we need more of. To the best of my knowledge, the pro-life stance isn't about creating a home for a stranger. That's what parenthood is about, but I don't see a direct connection to abortion. People like Marc Ouellet are pro-life because it lets them cultivate a sense of moral superiority over other people. Likewise, the entire fearmongering trend is about cultivating a sense of ethnic superiority over others. The two go together quite well.
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The important thing here is that the memory area which contain the signal must be aligned, but that's not all: '''the message should be placed 12 bytes after the base address of the aligned memory area'''. The address passed to mfc_sndsig is the address at which the message resides (base_address + 12bytes).
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<pre>
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/*
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* =============================================================================
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*      Filename:  spusend.c
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*    Description:  sends a signal to "spe1"
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*        Author:  Alessandro Piras (laynor@gmail.com)
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* =============================================================================
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*/
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#include <spu_intrinsics.h>
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#include <spu_mfcio.h>
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#include <stdio.h>
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int main(unsigned long long spe_id __attribute__ ((unused)),
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unsigned long long argp __attribute__ ((unused)),
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unsigned long long envp __attribute__ ((unused)))
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{
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unsigned int ps_area_ptr;
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//the memory area must be aligned
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volatile unsigned int signal[4] __attribute__ ((aligned (128)));
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//the message should be placed 3 bytes after
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signal[3] = 201;
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ps_area_ptr = spu_read_in_mbox();
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printf("(spe) ps_area_ptr: %x\
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", ps_area_ptr);
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//NB: the address passed is base address + 12 bytes
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mfc_sndsig(((char *) &signal[0]) + 12,
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ps_area_ptr, 31, 0, 0);
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mfc_write_tag_mask(1<<31);
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mfc_read_tag_status_all();
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return 0;
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}
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</pre>
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==SPE side: receiver==
==SPE side: receiver==

Revision as of 19:12, 20 November 2015

This tutorial shows how to send signals from one spe to another.

There are three entities in this tutorial:

  • starter: the PPE process who starts the spe threads
  • sender: the SPE thread who sends the signal
  • receiver the SPE thread who receives the signal

WAN Clustering allows you to scpfiey alternate IP's for NetConnect profiles, since they may differ on a cluster member at a remote site. If WAN Cluster is being deprecated then there needs to be a way to map a role to a correct netconnect profiles for a device. Currently there is no way to find out a unique identifier for the device (Serial Number/MAC/Device Name) to facilitate the mapping to a correct NetConnect profile. Push Config can overwrite the incorrect NetConnect profile. Juniper Support have been a dead end when trying to deal with this (or any enhancement).

PPE side: starter

The process starter does basically this:

  1. creates the spe threads
  2. sends sender the address of the signal notify area of receiver
  3. joins the threads.

It's important to note that the contexts are created using the SPE_MAP_PS flag, because we want the problem state area of the SPEs to be mapped in the effective address space (the signals are sent with dma commands). 


/*
 * =============================================================================
 *       Filename:  ppusig.c
 *    Description:  starter
 *         Author:  Alessandro Piras (laynor@gmail.com) 
 * =============================================================================
 */

#define ZZ_CTX_CREATE 	-2
#define ZZ_PRG_LOAD 	-3
#define ZZ_CTX_RUN	-4
#define ZZ_PTH_CREATE	-5
#define ZZ_PTH_JOIN	-6

#include <stdio.h>
#include <libspe2.h>
#include <pthread.h>
#include <unistd.h>
#include <stdlib.h>
//#include <commonlib.h>

extern spe_program_handle_t spurecv;
extern spe_program_handle_t spusend;

void *pth_rtn(void *arg)
{
	unsigned int entry=SPE_DEFAULT_ENTRY;
	int rc;
	void *argp=NULL;
	void *envp=NULL;
	spe_context_ptr_t ctx;

	ctx = *((spe_context_ptr_t *) arg);

	rc = spe_context_run(ctx, &entry, 0, argp, envp, NULL);
	if(rc < 0) {
		perror("spe_context_run()");
		exit(ZZ_CTX_RUN);
	}
	pthread_exit(NULL);
}	

int main()
{
	spe_context_ptr_t ctx[2];
	pthread_t pth[2];
	unsigned int flags = SPE_MAP_PS;
	int i;
	spe_sig_notify_1_area_t *sig_area;
	unsigned int sig_area1;

	//-----CTX creation
	for(i=0; i<2; i++){
		ctx[i] = spe_context_create(flags, 0);
		if(ctx[i] == NULL){
			perror("spe_context_create()");
			exit(ZZ_CTX_CREATE);
		}
	}

	//-----PRG load
	if(spe_program_load(ctx[0],&spurecv)){
		perror("spe_program_load()");
		exit(ZZ_PRG_LOAD);
	}
	if(spe_program_load(ctx[1],&spusend)){
		perror("spe_program_load()");
		exit(ZZ_PRG_LOAD);
	}

	//-----PTH creation
	for(i=0; i<2; i++)
		if(pthread_create(&pth[i], NULL, pth_rtn, &ctx[i])){
			perror("pthread_create()");
			exit(ZZ_PTH_CREATE);
		}

	sig_area = spe_ps_area_get(ctx[0], SPE_SIG_NOTIFY_1_AREA);
	sig_area1 = (unsigned int) (&(sig_area->SPU_Sig_Notify_1));
	spe_in_mbox_write(ctx[1], &sig_area1, 1, 1);
	
	//-----PTH join
	for(i=0; i<2; i++)
		if(pthread_join(pth[i], NULL)){
			perror("pthread_join()");
			exit(ZZ_PTH_JOIN);
		}

	//-----CTX destruction
	for(i=0; i<2; i++)
		spe_context_destroy(ctx[i]);
	return 0;
}

It makes me sad that my immediate rietcaon is to think of the flaws in the author's arguments, because this is the sort of article we need more of. To the best of my knowledge, the pro-life stance isn't about creating a home for a stranger. That's what parenthood is about, but I don't see a direct connection to abortion. People like Marc Ouellet are pro-life because it lets them cultivate a sense of moral superiority over other people. Likewise, the entire fearmongering trend is about cultivating a sense of ethnic superiority over others. The two go together quite well.

SPE side: receiver

Not much to say here, it's pretty simple. 


/*
 * =============================================================================
 *       Filename:  spurecv.c
 *    Description:  Waits for a signal and prints it
 *         Author:  Alessandro Piras (laynor@gmail.com) 
 * =============================================================================
 */

#include <spu_intrinsics.h>
#include <spu_mfcio.h>
#include <stdio.h>

int main(unsigned long long spe_id __attribute__ ((unused)),
		unsigned long long argp __attribute__ ((unused)),
		unsigned long long envp __attribute__ ((unused)))
{

	unsigned int value;
	value = spu_read_signal1();
	printf("(recvr) value: %u\
", value);
	return 0;
}
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