From: Sai Praneeth Prakhya <sai.praneeth.prak...@intel.com>

The callback starts a child process and puts the child pid in created
resctrl group with specified memory bandwidth in schemata. The child
starts running benchmark.

Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prak...@intel.com>
Signed-off-by: Arshiya Hayatkhan Pathan <arshiya.hayatkhan.pat...@intel.com>
Signed-off-by: Fenghua Yu <fenghua...@intel.com>
---
 tools/testing/selftests/resctrl/resctrl.h     |  27 ++
 tools/testing/selftests/resctrl/resctrl_val.c | 272 ++++++++++++++++++
 2 files changed, 299 insertions(+)

diff --git a/tools/testing/selftests/resctrl/resctrl.h 
b/tools/testing/selftests/resctrl/resctrl.h
index 01822f6258af..9820af253d4d 100644
--- a/tools/testing/selftests/resctrl/resctrl.h
+++ b/tools/testing/selftests/resctrl/resctrl.h
@@ -3,6 +3,7 @@
 #ifndef RESCTRL_H
 #define RESCTRL_H
 #include <stdio.h>
+#include <stdarg.h>
 #include <errno.h>
 #include <sched.h>
 #include <stdlib.h>
@@ -28,9 +29,34 @@
                exit(EXIT_FAILURE);             \
        } while (0)
 
+/*
+ * resctrl_val_param:  resctrl test parameters
+ * @resctrl_val:       Resctrl feature (Eg: mbm, mba.. etc)
+ * @ctrlgrp:           Name of the control monitor group (con_mon grp)
+ * @mongrp:            Name of the monitor group (mon grp)
+ * @cpu_no:            CPU number to which the benchmark would be binded
+ * @span:              Memory bytes accessed in each benchmark iteration
+ * @mum_resctrlfs:     Should the resctrl FS be remounted?
+ * @filename:          Name of file to which the o/p should be written
+ * @bw_report:         Bandwidth report type (reads vs writes)
+ * @setup:             Call back function to setup test environment
+ */
+struct resctrl_val_param {
+       char    *resctrl_val;
+       char    ctrlgrp[64];
+       char    mongrp[64];
+       int     cpu_no;
+       int     span;
+       int     mum_resctrlfs;
+       char    filename[64];
+       char    *bw_report;
+       int     (*setup)(int num, ...);
+};
+
 pid_t bm_pid, ppid;
 
 int remount_resctrlfs(bool mum_resctrlfs);
+int umount_resctrlfs(void);
 char get_sock_num(int cpu_no);
 int validate_bw_report_request(char *bw_report);
 int validate_resctrl_feature_request(char *resctrl_val);
@@ -43,5 +69,6 @@ int write_bm_pid_to_resctrl(pid_t bm_pid, char *ctrlgrp, char 
*mongrp,
 int perf_event_open(struct perf_event_attr *hw_event, pid_t pid, int cpu,
                    int group_fd, unsigned long flags);
 int run_fill_buf(int span, int malloc_and_init_memory, int memflush, int op);
+int membw_val(char **benchmark_cmd, struct resctrl_val_param *param);
 
 #endif /* RESCTRL_H */
diff --git a/tools/testing/selftests/resctrl/resctrl_val.c 
b/tools/testing/selftests/resctrl/resctrl_val.c
index f381aafc0523..9a79bf669254 100644
--- a/tools/testing/selftests/resctrl/resctrl_val.c
+++ b/tools/testing/selftests/resctrl/resctrl_val.c
@@ -11,6 +11,7 @@
  */
 #include "resctrl.h"
 
+#define MB                     (1024 * 1024)
 #define UNCORE_IMC             "uncore_imc"
 #define READ_FILE_NAME         "events/cas_count_read"
 #define WRITE_FILE_NAME                "events/cas_count_write"
@@ -429,3 +430,274 @@ static unsigned long get_mem_bw_resctrl(void)
 
        return mbm_total;
 }
+
+pid_t bm_pid, ppid;
+
+static void ctrlc_handler(int signum, siginfo_t *info, void *ptr)
+{
+       kill(bm_pid, SIGKILL);
+       printf("Ending\n\n");
+
+       exit(EXIT_SUCCESS);
+}
+
+/*
+ * print_results_bw:   the memory bandwidth results are stored in a file
+ * @filename:          file that stores the results
+ * @bm_pid:            child pid that runs benchmark
+ * @bw_imc:            perf imc counter value
+ * @bw_resc:           memory bandwidth value
+ *
+ * Return:             0 on success. non-zero on failure.
+ */
+static int print_results_bw(char *filename,  int bm_pid, float bw_imc,
+                           unsigned long bw_resc)
+{
+       unsigned long diff = labs(bw_imc - bw_resc);
+       FILE *fp;
+
+       if (strcmp(filename, "stdio") == 0 || strcmp(filename, "stderr") == 0) {
+               printf("Pid: %d \t Mem_BW_iMC: %f \t ", bm_pid, bw_imc);
+               printf("Mem_BW_resc: %lu \t Difference: %lu\n", bw_resc, diff);
+       } else {
+               fp = fopen(filename, "a");
+               if (!fp) {
+                       perror("Cannot open results file");
+
+                       return errno;
+               }
+               if (fprintf(fp, "Pid: %d \t Mem_BW_iMC: %f \t Mem_BW_resc: %lu 
\t Difference: %lu\n",
+                           bm_pid, bw_imc, bw_resc, diff) <= 0) {
+                       fclose(fp);
+                       perror("Could not log results.");
+
+                       return errno;
+               }
+               fclose(fp);
+       }
+
+       return 0;
+}
+
+static int
+measure_vals(struct resctrl_val_param *param, unsigned long *bw_resc_start)
+{
+       unsigned long bw_imc, bw_resc, bw_resc_end;
+       int ret;
+
+       /*
+        * Measure memory bandwidth from resctrl and from
+        * another source which is perf imc value or could
+        * be something else if perf imc event is not available.
+        * Compare the two values to validate resctrl value.
+        * It takes 1sec to measure the data.
+        */
+       bw_imc = get_mem_bw_imc(param->cpu_no, param->bw_report);
+       if (bw_imc <= 0)
+               return bw_imc;
+
+       bw_resc_end = get_mem_bw_resctrl();
+       if (bw_resc_end <= 0)
+               return bw_resc_end;
+
+       bw_resc = (bw_resc_end - *bw_resc_start) / MB;
+       ret = print_results_bw(param->filename, bm_pid, bw_imc, bw_resc);
+       if (ret)
+               return ret;
+
+       *bw_resc_start = bw_resc_end;
+
+       return 0;
+}
+
+/*
+ * membw_val:          execute benchmark and measure memory bandwidth on
+ *                     the benchmark
+ * @benchmark_cmd:     benchmark command and its arguments
+ * @param:             parameters passed to membw_val()
+ *
+ * Return:             0 on success. non-zero on failure.
+ */
+int membw_val(char **benchmark_cmd, struct resctrl_val_param *param)
+{
+       int ret = 0, pipefd[2], pipe_message = 0;
+       char *resctrl_val = param->resctrl_val;
+       unsigned long bw_resc_start = 0;
+       struct sigaction sigact;
+       union sigval value;
+       FILE *fp;
+
+       if (strcmp(param->filename, "") == 0)
+               sprintf(param->filename, "stdio");
+
+       if (strcmp(param->bw_report, "") == 0)
+               param->bw_report = "total";
+
+       ret = validate_resctrl_feature_request(resctrl_val);
+       if (ret)
+               return ret;
+
+       if ((strcmp(resctrl_val, "mba")) == 0 ||
+           (strcmp(resctrl_val, "mbm")) == 0) {
+               ret = validate_bw_report_request(param->bw_report);
+               if (ret)
+                       return ret;
+       }
+
+       ret = remount_resctrlfs(param->mum_resctrlfs);
+       if (ret)
+               return ret;
+
+       /*
+        * If benchmark wasn't successfully started by child, then child should
+        * kill parent, so save parent's pid
+        */
+       ppid = getpid();
+
+       /* File based synchronization between parent and child */
+       fp = fopen("sig", "w");
+       if (!fp) {
+               perror("Failed to open sig file");
+
+               return -1;
+       }
+       if (fprintf(fp, "%d\n", 0) <= 0) {
+               perror("Unable to establish sync bw parent & child");
+               fclose(fp);
+
+               return -1;
+       }
+       fclose(fp);
+
+       if (pipe(pipefd)) {
+               perror("Unable to create pipe");
+
+               return -1;
+       }
+
+       /*
+        * Fork to start benchmark, save child's pid so that it can be killed
+        * when needed
+        */
+       bm_pid = fork();
+       if (bm_pid == -1) {
+               perror("Unable to fork");
+
+               return -1;
+       }
+
+       if (bm_pid == 0) {
+               /*
+                * Mask all signals except SIGUSR1, parent uses SIGUSR1 to
+                * start benchmark
+                */
+               sigfillset(&sigact.sa_mask);
+               sigdelset(&sigact.sa_mask, SIGUSR1);
+
+               sigact.sa_sigaction = run_benchmark;
+               sigact.sa_flags = SA_SIGINFO;
+
+               /* Register for "SIGUSR1" signal from parent */
+               if (sigaction(SIGUSR1, &sigact, NULL))
+                       PARENT_EXIT("Can't register child for signal");
+
+               /* Tell parent that child is ready */
+               close(pipefd[0]);
+               pipe_message = 1;
+               write(pipefd[1], &pipe_message, sizeof(pipe_message));
+               close(pipefd[1]);
+
+               /* Suspend child until delivery of "SIGUSR1" from parent */
+               sigsuspend(&sigact.sa_mask);
+
+               PARENT_EXIT("Child is done");
+       }
+
+       printf("Benchmark PID: %d\n", bm_pid);
+
+       /*
+        * Register CTRL-C handler for parent, as it has to kill benchmark
+        * before exiting
+        */
+       sigact.sa_sigaction = ctrlc_handler;
+       sigemptyset(&sigact.sa_mask);
+       sigact.sa_flags = SA_SIGINFO;
+       if (sigaction(SIGINT, &sigact, NULL) ||
+           sigaction(SIGHUP, &sigact, NULL)) {
+               perror("Can't register parent for CTRL-C handler");
+               ret = errno;
+               goto out;
+       }
+
+       value.sival_ptr = benchmark_cmd;
+
+       /* Taskset benchmark to specified cpu */
+       ret = taskset_benchmark(bm_pid, param->cpu_no);
+       if (ret)
+               goto out;
+
+       /* Write benchmark to specified control&monitoring grp in resctrl FS */
+       ret = write_bm_pid_to_resctrl(bm_pid, param->ctrlgrp, param->mongrp,
+                                     resctrl_val);
+       if (ret)
+               goto out;
+
+       if ((strcmp(resctrl_val, "mbm") == 0) ||
+           (strcmp(resctrl_val, "mba") == 0)) {
+               ret = initialize_mem_bw_imc();
+               if (ret)
+                       goto out;
+
+               initialize_mem_bw_resctrl(param->ctrlgrp, param->mongrp,
+                                         param->cpu_no, resctrl_val);
+       }
+
+       /* Parent waits for child to be ready. */
+       close(pipefd[1]);
+       while (pipe_message != 1)
+               read(pipefd[0], &pipe_message, sizeof(pipe_message));
+       close(pipefd[0]);
+
+       /* Signal child to start benchmark */
+       if (sigqueue(bm_pid, SIGUSR1, value) == -1) {
+               perror("Unable to signal child to start execution");
+               ret = errno;
+               goto out;
+       }
+
+       /* Give benchmark enough time to fully run */
+       sleep(1);
+
+       /* Test runs until the callback setup() tells the test to stop. */
+       while (1) {
+               if (strcmp(resctrl_val, "mbm") == 0) {
+                       ret = param->setup(1, param);
+                       if (ret) {
+                               ret = 0;
+                               break;
+                       }
+
+                       ret = measure_vals(param, &bw_resc_start);
+                       if (ret)
+                               break;
+               } else if ((strcmp(resctrl_val, "mba") == 0)) {
+                       ret = param->setup(1, param);
+                       if (ret) {
+                               ret = 0;
+                               break;
+                       }
+
+                       ret = measure_vals(param, &bw_resc_start);
+                       if (ret)
+                               break;
+               } else {
+                       break;
+               }
+       }
+
+out:
+       kill(bm_pid, SIGKILL);
+       umount_resctrlfs();
+
+       return ret;
+}
-- 
2.19.1

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