[DTrace-devel] [PATCH v2 2/5] Add -xcpu support to dtrace provider
eugene.loh at oracle.com
eugene.loh at oracle.com
Thu Jan 11 05:13:30 UTC 2024
From: Eugene Loh <eugene.loh at oracle.com>
Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
---
libdtrace/dt_impl.h | 1 +
libdtrace/dt_work.c | 126 ++++++++++++++++++++++++-
test/unittest/options/tst.cpu-BEGIN.sh | 22 +++++
test/unittest/options/tst.cpu-END.sh | 22 +++++
4 files changed, 169 insertions(+), 2 deletions(-)
create mode 100755 test/unittest/options/tst.cpu-BEGIN.sh
create mode 100755 test/unittest/options/tst.cpu-END.sh
diff --git a/libdtrace/dt_impl.h b/libdtrace/dt_impl.h
index 6c261f69..9912ad65 100644
--- a/libdtrace/dt_impl.h
+++ b/libdtrace/dt_impl.h
@@ -414,6 +414,7 @@ struct dtrace_hdl {
uint_t dt_stopped; /* boolean: set once tracing is stopped */
processorid_t dt_beganon; /* CPU that executed BEGIN probe (if any) */
processorid_t dt_endedon; /* CPU that executed END probe (if any) */
+ void *dt_beginendargs; /* args for child running BEGIN and END probes */
uint_t dt_oflags; /* dtrace open-time options (see dtrace.h) */
uint_t dt_cflags; /* dtrace compile-time options (see dtrace.h) */
uint_t dt_dflags; /* dtrace link-time options (see dtrace.h) */
diff --git a/libdtrace/dt_work.c b/libdtrace/dt_work.c
index fe88a48e..9946f30e 100644
--- a/libdtrace/dt_work.c
+++ b/libdtrace/dt_work.c
@@ -131,6 +131,76 @@ dtrace_status(dtrace_hdl_t *dtp)
return DTRACE_STATUS_OKAY;
}
+#define CMD_BEGIN 1234
+#define CMD_END 5678
+typedef struct dt_beginendargs {
+ pthread_t thr;
+ processorid_t cpu;
+ processorid_t ncpus;
+ int tochild[2];
+ int frchild[2];
+} dt_beginendargs_t;
+
+static
+void bind_to_cpu(int cpu, int ncpus) {
+ cpu_set_t *mask;
+ size_t size;
+
+ /* Allocate the CPU mask and get its size. */
+ mask = CPU_ALLOC(ncpus);
+ if (mask == NULL)
+ exit(1);
+ size = CPU_ALLOC_SIZE(ncpus);
+
+ /* Set the CPU mask. */
+ CPU_ZERO_S(size, mask);
+ CPU_SET_S(cpu, size, mask);
+
+ /* Set my affinity. */
+ if (sched_setaffinity(0, size, mask) != 0) {
+ /* FIXME: some other failure mode? */
+ exit(1);
+ }
+
+ /* Free the mask. */
+ CPU_FREE(mask);
+}
+
+static unsigned long long
+elapsed_msecs() {
+ struct timespec tstruct;
+
+ clock_gettime(CLOCK_MONOTONIC, &tstruct);
+ return tstruct.tv_sec * 1000ull + tstruct.tv_nsec / 1000000;
+}
+
+static void *
+beginend_child(void *arg) {
+ dt_beginendargs_t *args = arg;
+ int cmd = 0;
+
+ /* Bind to requested CPU. */
+ bind_to_cpu(args->cpu, args->ncpus);
+
+ /* Wait for command, call BEGIN_probe(), and ack. */
+ read(args->tochild[0], &cmd, sizeof(cmd));
+ if (cmd != CMD_BEGIN)
+ exit(1);
+ BEGIN_probe();
+ cmd++;
+ write(args->frchild[1], &cmd, sizeof(cmd));
+
+ /* Wait for command, call END_probe(), and ack. */
+ read(args->tochild[0], &cmd, sizeof(cmd));
+ if (cmd != CMD_END)
+ exit(1);
+ END_probe();
+ cmd++;
+ write(args->frchild[1], &cmd, sizeof(cmd));
+
+ pthread_exit(0);
+}
+
int
dtrace_go(dtrace_hdl_t *dtp, uint_t cflags)
{
@@ -140,6 +210,27 @@ dtrace_go(dtrace_hdl_t *dtp, uint_t cflags)
if (dtp->dt_active)
return dt_set_errno(dtp, EINVAL);
+ /*
+ * Create a child for the BEGIN and END probes if -xcpu is used.
+ */
+ if (dtp->dt_options[DTRACEOPT_CPU] != DTRACEOPT_UNSET) {
+ dt_beginendargs_t *args;
+
+ args = dt_zalloc(dtp, sizeof(dt_beginendargs_t));
+ if (args == NULL)
+ return dt_set_errno(dtp, EDT_NOMEM);
+ pipe(args->tochild);
+ pipe2(args->frchild, O_NONBLOCK);
+ args->cpu = dtp->dt_options[DTRACEOPT_CPU];
+ args->ncpus = dtp->dt_conf.max_cpuid + 1;
+
+ if (pthread_create(&args->thr, NULL, &beginend_child, args)) {
+ printf("error pthread_create for -xcpu\n");
+ return -1;
+ }
+ dtp->dt_beginendargs = args;
+ }
+
/* Create the BPF programs. */
if (dt_bpf_make_progs(dtp, cflags) == -1)
return -1;
@@ -190,7 +281,22 @@ dtrace_go(dtrace_hdl_t *dtp, uint_t cflags)
if (dt_aggregate_go(dtp) == -1)
return -1;
- if (RUNNING_ON_VALGRIND)
+ if (dtp->dt_beginendargs) {
+ /* Tell child running on a specific CPU to BEGIN. */
+ dt_beginendargs_t *args = dtp->dt_beginendargs;
+ unsigned long long timeout;
+ int cmd = CMD_BEGIN;
+
+ write(args->tochild[1], &cmd, sizeof(cmd));
+ timeout = elapsed_msecs() + 2000;
+ while (read(args->frchild[0], &cmd, sizeof(cmd)) <= 0) {
+ usleep(100000);
+ if (elapsed_msecs() > timeout)
+ return -1;
+ }
+ if (cmd != CMD_BEGIN + 1)
+ return -1;
+ } else if (RUNNING_ON_VALGRIND)
VALGRIND_NON_SIMD_CALL0(BEGIN_probe);
else
BEGIN_probe();
@@ -223,7 +329,23 @@ dtrace_stop(dtrace_hdl_t *dtp)
if (dt_state_get_activity(dtp) < DT_ACTIVITY_DRAINING)
dt_state_set_activity(dtp, DT_ACTIVITY_DRAINING);
- if (RUNNING_ON_VALGRIND)
+ if (dtp->dt_beginendargs) {
+ int cmd = CMD_END;
+ dt_beginendargs_t *args = dtp->dt_beginendargs;
+ unsigned long long timeout;
+
+ write(args->tochild[1], &cmd, sizeof(cmd));
+ timeout = elapsed_msecs() + 2000;
+ while (read(args->frchild[0], &cmd, sizeof(cmd)) <= 0) {
+ usleep(100000);
+ if (elapsed_msecs() > timeout)
+ return -1;
+ }
+ if (cmd != CMD_END + 1)
+ return -1;
+ pthread_join(args->thr, NULL);
+ dt_free(dtp, args);
+ } else if (RUNNING_ON_VALGRIND)
VALGRIND_NON_SIMD_CALL0(END_probe);
else
END_probe();
diff --git a/test/unittest/options/tst.cpu-BEGIN.sh b/test/unittest/options/tst.cpu-BEGIN.sh
new file mode 100755
index 00000000..793ece8f
--- /dev/null
+++ b/test/unittest/options/tst.cpu-BEGIN.sh
@@ -0,0 +1,22 @@
+#!/bin/bash
+#
+# Oracle Linux DTrace.
+# Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+# Licensed under the Universal Permissive License v 1.0 as shown at
+# http://oss.oracle.com/licenses/upl.
+#
+
+dtrace=$1
+
+nerr=0
+for cpu0 in `awk '/^processor[ ]*: [0-9]*$/ {print $3}' /proc/cpuinfo`; do
+ cpu=`$dtrace $dt_flags -xcpu=$cpu0 -qn 'BEGIN { trace(cpu); exit(0); }'`
+ echo expected cpu $cpu0 got cpu $cpu
+ if [ `echo $cpu | wc -w` -ne 1 ]; then
+ nerr=$(($nerr + 1))
+ elif [ $(($cpu + 0)) != $cpu0 ]; then
+ nerr=$(($nerr + 1))
+ fi
+done
+
+exit $nerr
diff --git a/test/unittest/options/tst.cpu-END.sh b/test/unittest/options/tst.cpu-END.sh
new file mode 100755
index 00000000..b77cbf3c
--- /dev/null
+++ b/test/unittest/options/tst.cpu-END.sh
@@ -0,0 +1,22 @@
+#!/bin/bash
+#
+# Oracle Linux DTrace.
+# Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+# Licensed under the Universal Permissive License v 1.0 as shown at
+# http://oss.oracle.com/licenses/upl.
+#
+
+dtrace=$1
+
+nerr=0
+for cpu0 in `awk '/^processor[ ]*: [0-9]*$/ {print $3}' /proc/cpuinfo`; do
+ cpu=`$dtrace $dt_flags -xcpu=$cpu0 -qn 'BEGIN { exit(0) } END { trace(cpu); }'`
+ echo expected cpu $cpu0 got cpu $cpu
+ if [ `echo $cpu | wc -w` -ne 1 ]; then
+ nerr=$(($nerr + 1))
+ elif [ $(($cpu + 0)) != $cpu0 ]; then
+ nerr=$(($nerr + 1))
+ fi
+done
+
+exit $nerr
--
2.18.4
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