[DTrace-devel] [PATCH v3 1/2] Implement the sched provider (first part)
Eugene Loh
eugene.loh at oracle.com
Wed May 24 15:13:05 UTC 2023
Thanks for the tests, but none of them check output??? Those are
barebones tests. There should be correctness tests, "dtrace -l",
"dtrace -lv", and correctness of args. Or at least sanity checks of
correctness.
I don't know if there should be a "#undef ENQUEUE_HEAD". Not practical,
but I don't know if we have a style in this regard.
The trampoline is relatively simple, but still some codegen functions
might be useful (as done in the lockstat provider), both to separate
codegen reasoning from instrumentation reasoning and to look more
similar to lockstat.
On 5/24/23 02:07, Kris Van Hees via DTrace-devel wrote:
> Partial implementation of the sched SDT provider. The following probes
> are implemented:
>
> sched:::dequeue (arg1 is NULL)
> sched:::enqueue (arg1 is NULL)
> sched:::off-cpu
> sched:::on-cpu (limited trigger locations)
> sched:::surrender
> sched:::tick
> sched:::wakeup
>
> Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
> Reviewed-by: Nick Alcock <nick.alcock at oracle.com>
> ---
> libdtrace/Build | 2 +
> libdtrace/dt_open.c | 1 +
> libdtrace/dt_prov_sched.c | 151 +++++++++++++++++++++++++
> libdtrace/dt_provider.h | 1 +
> test/demo/sched/dtrace.d | 1 -
> test/demo/sched/howlong.d | 1 -
> test/demo/sched/qlen.d | 1 -
> test/demo/sched/qtime.d | 1 -
> test/demo/sched/tick.d | 1 -
> test/demo/sched/ticktime.d | 1 -
> test/demo/sched/where.d | 1 -
> test/demo/sched/whoqueue.d | 1 -
> test/demo/sched/whosteal.d | 1 -
> test/unittest/buffering/tst.cputime.sh | 1 -
> 14 files changed, 155 insertions(+), 10 deletions(-)
> create mode 100644 libdtrace/dt_prov_sched.c
>
> diff --git a/libdtrace/Build b/libdtrace/Build
> index cf18a043..89972c66 100644
> --- a/libdtrace/Build
> +++ b/libdtrace/Build
> @@ -52,6 +52,7 @@ libdtrace-build_SOURCES = dt_aggregate.c \
> dt_prov_proc.c \
> dt_prov_profile.c \
> dt_prov_rawtp.c \
> + dt_prov_sched.c \
> dt_prov_sdt.c \
> dt_prov_syscall.c \
> dt_prov_uprobe.c \
> @@ -96,6 +97,7 @@ dt_prov_fbt.c_CFLAGS := -Wno-pedantic
> dt_prov_proc.c_CFLAGS := -Wno-pedantic
> dt_prov_profile.c_CFLAGS := -Wno-pedantic
> dt_prov_rawtp.c_CFLAGS := -Wno-pedantic
> +dt_prov_sched.c_CFLAGS := -Wno-pedantic
> dt_prov_sdt.c_CFLAGS := -Wno-pedantic
> dt_prov_syscall.c_CFLAGS := -Wno-pedantic
> dt_prov_uprobe.c_CFLAGS := -Wno-pedantic
> diff --git a/libdtrace/dt_open.c b/libdtrace/dt_open.c
> index d13b859a..110d45bc 100644
> --- a/libdtrace/dt_open.c
> +++ b/libdtrace/dt_open.c
> @@ -71,6 +71,7 @@ static const dt_provimpl_t *dt_providers[] = {
> &dt_proc,
> &dt_profile,
> &dt_rawtp,
> + &dt_sched,
> &dt_sdt,
> &dt_syscall,
> &dt_uprobe,
> diff --git a/libdtrace/dt_prov_sched.c b/libdtrace/dt_prov_sched.c
> new file mode 100644
> index 00000000..8703c936
> --- /dev/null
> +++ b/libdtrace/dt_prov_sched.c
> @@ -0,0 +1,151 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2023, 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.
> + *
> + * The 'sched' SDT provider for DTrace-specific probes.
> + */
> +#include <assert.h>
> +#include <errno.h>
> +
> +#include "dt_dctx.h"
> +#include "dt_cg.h"
> +#include "dt_provider_sdt.h"
> +#include "dt_probe.h"
> +
> +static const char prvname[] = "sched";
> +static const char modname[] = "vmlinux";
> +
> +static probe_dep_t probes[] = {
> + { "dequeue",
> + DTRACE_PROBESPEC_NAME, "fbt::dequeue_task_*:entry" },
> + { "enqueue",
> + DTRACE_PROBESPEC_NAME, "fbt::enqueue_task_*:entry" },
> + { "off-cpu",
> + DTRACE_PROBESPEC_NAME, "rawtp:sched::sched_switch" },
> + { "on-cpu",
> + DTRACE_PROBESPEC_NAME, "fbt::schedule_tail:entry" },
> + { "surrender",
> + DTRACE_PROBESPEC_NAME, "fbt::do_sched_yield:entry" },
> + { "tick",
> + DTRACE_PROBESPEC_NAME, "fbt::scheduler_tick:entry" },
> + { "wakeup",
> + DTRACE_PROBESPEC_NAME, "rawtp:sched::sched_wakeup" },
> + { NULL, }
> +};
> +
> +static probe_arg_t probe_args[] = {
> +#if 0
> + { "change-pri", 0, { 0, 0, "struct task_struct *", "lwpsinfo_t *" } },
> + { "change-pri", 1, { 0, 0, "struct task_struct *", "psinfo_t *" } },
> + { "change-pri", 2, { 1, 0, "int", } },
> +#endif
> + { "dequeue", 0, { 0, 0, "struct task_struct *", "lwpsinfo_t *" } },
> + { "dequeue", 1, { 0, 0, "struct task_struct *", "psinfo_t *" } },
> + { "dequeue", 2, { 1, 0, "cpuinfo_t *", } },
> + { "dequeue", 3, { 2, 0, "int", } },
> + { "enqueue", 0, { 0, 0, "struct task_struct *", "lwpsinfo_t *" } },
> + { "enqueue", 1, { 0, 0, "struct task_struct *", "psinfo_t *" } },
> + { "enqueue", 2, { 1, 0, "cpuinfo_t *", } },
> + { "off-cpu", 0, { 0, 0, "struct task_struct *", "lwpsinfo_t *" } },
> + { "off-cpu", 1, { 0, 0, "struct task_struct *", "psinfo_t *" } },
> + { "on-cpu", },
> +#if 0
> + { "preempt", },
> + { "remain-cpu", },
> + { "sleep", },
> +#endif
> + { "surrender", 0, { 0, 0, "struct task_struct *", "lwpsinfo_t *" } },
> + { "surrender", 1, { 0, 0, "struct task_struct *", "psinfo_t *" } },
> + { "tick", 0, { 0, 0, "struct task_struct *", "lwpsinfo_t *" } },
> + { "tick", 1, { 0, 0, "struct task_struct *", "psinfo_t *" } },
> + { "wakeup", 0, { 0, 0, "struct task_struct *", "lwpsinfo_t *" } },
> + { "wakeup", 1, { 0, 0, "struct task_struct *", "psinfo_t *" } },
> + { NULL, }
> +};
> +
> +static const dtrace_pattr_t pattr = {
> +{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA },
> +{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
> +{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
> +{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA },
> +{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA },
> +};
> +
> +/*
> + * Provide all the "sched" SDT probes.
> + */
> +static int populate(dtrace_hdl_t *dtp)
> +{
> + return dt_sdt_populate(dtp, prvname, modname, &dt_sched, &pattr,
> + probe_args, probes);
> +}
> +
> +/*
> + * Generate a BPF trampoline for a SDT probe.
> + *
> + * The trampoline function is called when a SDT probe triggers, and it must
> + * satisfy the following prototype:
> + *
> + * int dt_sched(void *data)
> + *
> + * The trampoline will populate a dt_dctx_t struct and then call the function
> + * that implements the compiled D clause. It returns the value that it gets
> + * back from that function.
> + */
> +static int trampoline(dt_pcb_t *pcb, uint_t exitlbl)
> +{
> + dt_irlist_t *dlp = &pcb->pcb_ir;
> + dt_probe_t *prp = pcb->pcb_probe;
> +
> + if (strcmp(prp->desc->prb, "dequeue") == 0) {
> + emit(dlp, BPF_LOAD(BPF_DW, BPF_REG_0, BPF_REG_7, DMST_ARG(1)));
> + emit(dlp, BPF_STORE(BPF_DW, BPF_REG_7, DMST_ARG(0), BPF_REG_0));
> + /*
> + * FIXME: arg1 should be a pointer to cpuinfo_t for the CPU
> + * associated with the runqueue.
> + */
> + emit(dlp, BPF_STORE_IMM(BPF_DW, BPF_REG_7, DMST_ARG(1), 0));
> + } else if (strcmp(prp->desc->prb, "enqueue") == 0) {
> +/*
> + * This is ugly but necessary... enqueue_task() takes a flags argument and the
> + * ENQUEUE_HEAD flag is used to indicate that the task is to be placed at the
> + * head of the queue. We need to be able to pass this special case as arg2
> + * in the enqueue probe.
> + *
> + * The flag values are found in kernel/sched/sched.h which is not exposed
> + * outside the kernel source tree.
> + */
> +#define ENQUEUE_HEAD 0x10
> +
> + emit(dlp, BPF_LOAD(BPF_DW, BPF_REG_0, BPF_REG_7, DMST_ARG(1)));
> + emit(dlp, BPF_STORE(BPF_DW, BPF_REG_7, DMST_ARG(0), BPF_REG_0));
> + /*
> + * FIXME: arg1 should be a pointer to cpuinfo_t for the CPU
> + * associated with the runqueue.
> + */
> + emit(dlp, BPF_STORE_IMM(BPF_DW, BPF_REG_7, DMST_ARG(1), 0));
> + emit(dlp, BPF_LOAD(BPF_DW, BPF_REG_0, BPF_REG_7, DMST_ARG(2)));
> + emit(dlp, BPF_ALU64_IMM(BPF_AND, BPF_REG_0, ENQUEUE_HEAD));
> + emit(dlp, BPF_STORE(BPF_DW, BPF_REG_7, DMST_ARG(2), BPF_REG_0));
> + } else if (strcmp(prp->desc->prb, "off-cpu") == 0) {
> + emit(dlp, BPF_LOAD(BPF_DW, BPF_REG_0, BPF_REG_7, DMST_ARG(2)));
> + emit(dlp, BPF_STORE(BPF_DW, BPF_REG_7, DMST_ARG(0), BPF_REG_0));
> + } else if (strcmp(prp->desc->prb, "surrender") == 0 ||
> + strcmp(prp->desc->prb, "tick") == 0) {
> + emit(dlp, BPF_CALL_HELPER(BPF_FUNC_get_current_task));
> + emit(dlp, BPF_STORE(BPF_DW, BPF_REG_7, DMST_ARG(0), BPF_REG_0));
> + }
> +
> + return 0;
> +}
> +
> +dt_provimpl_t dt_sched = {
> + .name = prvname,
> + .prog_type = BPF_PROG_TYPE_UNSPEC,
> + .populate = &populate,
> + .enable = &dt_sdt_enable,
> + .trampoline = &trampoline,
> + .probe_info = &dt_sdt_probe_info,
> +};
> diff --git a/libdtrace/dt_provider.h b/libdtrace/dt_provider.h
> index 068c65a2..252a73d4 100644
> --- a/libdtrace/dt_provider.h
> +++ b/libdtrace/dt_provider.h
> @@ -73,6 +73,7 @@ extern dt_provimpl_t dt_fbt;
> extern dt_provimpl_t dt_proc;
> extern dt_provimpl_t dt_profile;
> extern dt_provimpl_t dt_rawtp;
> +extern dt_provimpl_t dt_sched;
> extern dt_provimpl_t dt_sdt;
> extern dt_provimpl_t dt_syscall;
> extern dt_provimpl_t dt_uprobe;
> diff --git a/test/demo/sched/dtrace.d b/test/demo/sched/dtrace.d
> index cedffb53..a1e9b4a8 100644
> --- a/test/demo/sched/dtrace.d
> +++ b/test/demo/sched/dtrace.d
> @@ -4,7 +4,6 @@
> * Licensed under the Universal Permissive License v 1.0 as shown at
> * http://oss.oracle.com/licenses/upl.
> */
> -/* @@xfail: dtv2 */
>
> #pragma D option quiet
>
> diff --git a/test/demo/sched/howlong.d b/test/demo/sched/howlong.d
> index f68239e9..ace1b8fc 100644
> --- a/test/demo/sched/howlong.d
> +++ b/test/demo/sched/howlong.d
> @@ -4,7 +4,6 @@
> * Licensed under the Universal Permissive License v 1.0 as shown at
> * http://oss.oracle.com/licenses/upl.
> */
> -/* @@xfail: dtv2 */
>
> sched:::off-cpu
> /curlwpsinfo->pr_state == SSLEEP/
> diff --git a/test/demo/sched/qlen.d b/test/demo/sched/qlen.d
> index 029cbbf6..95025bd6 100644
> --- a/test/demo/sched/qlen.d
> +++ b/test/demo/sched/qlen.d
> @@ -4,7 +4,6 @@
> * Licensed under the Universal Permissive License v 1.0 as shown at
> * http://oss.oracle.com/licenses/upl.
> */
> -/* @@xfail: dtv2 */
>
> sched:::enqueue
> {
> diff --git a/test/demo/sched/qtime.d b/test/demo/sched/qtime.d
> index ba010f3e..344a88ea 100644
> --- a/test/demo/sched/qtime.d
> +++ b/test/demo/sched/qtime.d
> @@ -4,7 +4,6 @@
> * Licensed under the Universal Permissive License v 1.0 as shown at
> * http://oss.oracle.com/licenses/upl.
> */
> -/* @@xfail: dtv2 */
>
> sched:::enqueue
> {
> diff --git a/test/demo/sched/tick.d b/test/demo/sched/tick.d
> index 54d18d70..57376f1f 100644
> --- a/test/demo/sched/tick.d
> +++ b/test/demo/sched/tick.d
> @@ -4,7 +4,6 @@
> * Licensed under the Universal Permissive License v 1.0 as shown at
> * http://oss.oracle.com/licenses/upl.
> */
> -/* @@xfail: dtv2 */
>
> sched:::tick,
> sched:::enqueue
> diff --git a/test/demo/sched/ticktime.d b/test/demo/sched/ticktime.d
> index 3fd0bfbc..dca76dba 100644
> --- a/test/demo/sched/ticktime.d
> +++ b/test/demo/sched/ticktime.d
> @@ -4,7 +4,6 @@
> * Licensed under the Universal Permissive License v 1.0 as shown at
> * http://oss.oracle.com/licenses/upl.
> */
> -/* @@xfail: dtv2 */
>
> uint64_t last[int];
>
> diff --git a/test/demo/sched/where.d b/test/demo/sched/where.d
> index 8845610d..906920d0 100644
> --- a/test/demo/sched/where.d
> +++ b/test/demo/sched/where.d
> @@ -4,7 +4,6 @@
> * Licensed under the Universal Permissive License v 1.0 as shown at
> * http://oss.oracle.com/licenses/upl.
> */
> -/* @@xfail: dtv2 */
>
> sched:::on-cpu
> {
> diff --git a/test/demo/sched/whoqueue.d b/test/demo/sched/whoqueue.d
> index 3057600c..1eb3d1b4 100644
> --- a/test/demo/sched/whoqueue.d
> +++ b/test/demo/sched/whoqueue.d
> @@ -4,7 +4,6 @@
> * Licensed under the Universal Permissive License v 1.0 as shown at
> * http://oss.oracle.com/licenses/upl.
> */
> -/* @@xfail: dtv2 */
>
> #pragma D option quiet
> #pragma D option nspec=4
> diff --git a/test/demo/sched/whosteal.d b/test/demo/sched/whosteal.d
> index 5ac091b3..5287dd99 100644
> --- a/test/demo/sched/whosteal.d
> +++ b/test/demo/sched/whosteal.d
> @@ -4,7 +4,6 @@
> * Licensed under the Universal Permissive License v 1.0 as shown at
> * http://oss.oracle.com/licenses/upl.
> */
> -/* @@xfail: dtv2 */
>
> #pragma D option quiet
>
> diff --git a/test/unittest/buffering/tst.cputime.sh b/test/unittest/buffering/tst.cputime.sh
> index cde1fba0..6a420e8d 100755
> --- a/test/unittest/buffering/tst.cputime.sh
> +++ b/test/unittest/buffering/tst.cputime.sh
> @@ -6,7 +6,6 @@
> # http://oss.oracle.com/licenses/upl.
> #
> # @@timeout: 12
> -# @@xfail: dtv2
>
> script()
> {
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