* Christophe de Dinechin (dinec...@redhat.com) wrote:
> The recorder library provides support for low-cost continuous
> recording of events, which can then be replayed. This makes it
> possible to collect data "after the fact",for example to show the
> events that led to a crash.
>
> Recorder support in qemu is implemented using the existing tracing
> interface. In addition, it is possible to individually enable
> recorders that are not traces, although this is probably not
> recommended.
>
> HMP COMMAND:
> The 'recorder' hmp command has been added, which supports two
> sub-commands:
> - recorder dump: Dump the current state of the recorder. You can
^^^^^^^^
is that intended?
> - recorder trace: Set traces using the recorder_trace_set() syntax.
> You can use "recorder trace help" to list all available recorders.
>
> Signed-off-by: Christophe de Dinechin <dinec...@redhat.com>
> ---
> configure | 5 +++
> hmp-commands.hx | 19 ++++++++--
> monitor/misc.c | 27 ++++++++++++++
> scripts/tracetool/backend/recorder.py | 51 +++++++++++++++++++++++++++
> trace/Makefile.objs | 2 ++
> trace/control.c | 7 ++++
> trace/recorder.c | 22 ++++++++++++
> trace/recorder.h | 34 ++++++++++++++++++
> util/module.c | 8 +++++
> 9 files changed, 173 insertions(+), 2 deletions(-)
> create mode 100644 scripts/tracetool/backend/recorder.py
> create mode 100644 trace/recorder.c
> create mode 100644 trace/recorder.h
>
> diff --git a/configure b/configure
> index ae8737d5a2..130630b98f 100755
> --- a/configure
> +++ b/configure
> @@ -7702,6 +7702,11 @@ fi
> if have_backend "log"; then
> echo "CONFIG_TRACE_LOG=y" >> $config_host_mak
> fi
> +if have_backend "recorder"; then
> + echo "CONFIG_TRACE_RECORDER=y" >> $config_host_mak
> + # This is a bit brutal, but there is currently a bug in the makefiles
> + LIBS="$LIBS -lrecorder"
> +fi
> if have_backend "ust"; then
> echo "CONFIG_TRACE_UST=y" >> $config_host_mak
> fi
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 60f395c276..565f518d4b 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -297,6 +297,22 @@ ERST
> .cmd = hmp_trace_file,
> },
>
> +SRST
> +``trace-file on|off|flush``
> + Open, close, or flush the trace file. If no argument is given, the
> + status of the trace file is displayed.
> +ERST
> +#endif
> +
> +#if defined(CONFIG_TRACE_RECORDER)
> + {
> + .name = "recorder",
> + .args_type = "op:s?,arg:F?",
Having 'arg' as a filename is a bit odd; using op/arg is very generic
for adding extra commands; but it suddenly becomes less generic if
arg is always a filename.
> + .params = "trace|dump [arg]",
> + .help = "trace selected recorders or print recorder dump",
> + .cmd = hmp_recorder,
> + },
> +
> SRST
> ``trace-file on|off|flush``
> Open, close, or flush the trace file. If no argument is given, the
I think this SRST chunk is the one that needs updating for recorder.
(The diff has made a bit of a mess, but I think you've copy pasted the
trace-file chunk, but forgotten to update the SRST section).
> @@ -1120,7 +1136,7 @@ ERST
>
> SRST
> ``dump-guest-memory [-p]`` *filename* *begin* *length*
> - \
> + \
> ``dump-guest-memory [-z|-l|-s|-w]`` *filename*
> Dump guest memory to *protocol*. The file can be processed with crash or
> gdb. Without ``-z|-l|-s|-w``, the dump format is ELF.
> @@ -1828,4 +1844,3 @@ ERST
> .sub_table = hmp_info_cmds,
> .flags = "p",
> },
> -
> diff --git a/monitor/misc.c b/monitor/misc.c
> index 89bb970b00..0094b1860f 100644
> --- a/monitor/misc.c
> +++ b/monitor/misc.c
> @@ -61,6 +61,9 @@
> #ifdef CONFIG_TRACE_SIMPLE
> #include "trace/simple.h"
> #endif
> +#ifdef CONFIG_TRACE_RECORDER
> +#include "trace/recorder.h"
> +#endif
> #include "exec/memory.h"
> #include "exec/exec-all.h"
> #include "qemu/option.h"
> @@ -227,6 +230,30 @@ static void hmp_trace_file(Monitor *mon, const QDict
> *qdict)
> }
> #endif
>
> +#ifdef CONFIG_TRACE_RECORDER
> +static void hmp_recorder(Monitor *mon, const QDict *qdict)
> +{
> + const char *op = qdict_get_try_str(qdict, "op");
> + const char *arg = qdict_get_try_str(qdict, "arg");
> +
> + if (!op) {
> + monitor_printf(mon, "missing recorder command\"%s\"\n", op);
> + help_cmd(mon, "recorder");
> + } else if (!strcmp(op, "trace")) {
> + recorder_trace_set(arg);
> + } else if (!strcmp(op, "dump")) {
> + if (!arg || !*arg) {
> + recorder_dump();
> + } else {
> + recorder_dump_for(arg);
> + }
> + } else {
> + monitor_printf(mon, "unexpected recorder command \"%s\"\n", op);
> + help_cmd(mon, "recorder");
> + }
> +}
Consider whether just doing two separate commands would be easier;
a recorder-trace and recorder-dump for example; that's fine from a HMP
point of view and I think you'll find it's less code.
Dave
> +#endif
> +
> static void hmp_info_help(Monitor *mon, const QDict *qdict)
> {
> help_cmd(mon, "info");
> diff --git a/scripts/tracetool/backend/recorder.py
> b/scripts/tracetool/backend/recorder.py
> new file mode 100644
> index 0000000000..79cc6f5b03
> --- /dev/null
> +++ b/scripts/tracetool/backend/recorder.py
> @@ -0,0 +1,51 @@
> +# -*- coding: utf-8 -*-
> +
> +"""
> +Trace back-end for recorder library
> +"""
> +
> +__author__ = "Christophe de Dinechin <christo...@dinechin.org>"
> +__copyright__ = "Copyright 2020, Christophe de Dinechin and Red Hat"
> +__license__ = "GPL version 2 or (at your option) any later version"
> +
> +__maintainer__ = "Christophe de Dinechin"
> +__email__ = "christo...@dinechin.org"
> +
> +
> +from tracetool import out
> +
> +PUBLIC = True
> +
> +def generate_h_begin(events, group):
> + out('#include <recorder/recorder.h>', '')
> +
> + for event in events:
> + out('RECORDER_DECLARE(%(name)s);', name=event.name)
> +
> +
> +def generate_h(event, group):
> + argnames = ", ".join(event.args.names())
> + if len(event.args) > 0:
> + argnames = ", " + argnames
> +
> + out(' record(%(event)s, %(fmt)s %(argnames)s);',
> + event=event.name,
> + fmt=event.fmt.rstrip("\n"),
> + argnames=argnames)
> +
> +
> +def generate_h_backend_dstate(event, group):
> + out(' RECORDER_TWEAK(%(event_id)s) || \\', event_id=event.name)
> +
> +def generate_c_begin(events, group):
> + out('#include "qemu/osdep.h"',
> + '#include "trace/control.h"',
> + '#include "trace/simple.h"',
> + '#include <recorder/recorder.h>',
> + '')
> +
> + for event in events:
> + out('RECORDER_DEFINE(%(name)s, 8, "Tracetool recorder for
> %(api)s(%(args)s)");',
> + name=event.name,
> + api=event.api(),
> + args=event.args)
> diff --git a/trace/Makefile.objs b/trace/Makefile.objs
> index c544509adf..9e347640c2 100644
> --- a/trace/Makefile.objs
> +++ b/trace/Makefile.objs
> @@ -54,6 +54,8 @@ $(obj)/generated-tcg-tracers.h-timestamp:
> $(SRC_PATH)/trace-events $(BUILD_DIR)/
>
> util-obj-$(CONFIG_TRACE_SIMPLE) += simple.o
> util-obj-$(CONFIG_TRACE_FTRACE) += ftrace.o
> +util-obj-$(CONFIG_TRACE_RECORDER) += recorder.o
> +recorder.o-libs = -lrecorder
> util-obj-y += control.o
> obj-y += control-target.o
> util-obj-y += qmp.o
> diff --git a/trace/control.c b/trace/control.c
> index 2ffe000818..15e5293eec 100644
> --- a/trace/control.c
> +++ b/trace/control.c
> @@ -23,6 +23,9 @@
> #ifdef CONFIG_TRACE_SYSLOG
> #include <syslog.h>
> #endif
> +#ifdef CONFIG_TRACE_RECORDER
> +#include "trace/recorder.h"
> +#endif
> #include "qapi/error.h"
> #include "qemu/error-report.h"
> #include "qemu/config-file.h"
> @@ -282,6 +285,10 @@ bool trace_init_backends(void)
> openlog(NULL, LOG_PID, LOG_DAEMON);
> #endif
>
> +#ifdef CONFIG_TRACE_RECORDER
> + recorder_trace_init();
> +#endif
> +
> return true;
> }
>
> diff --git a/trace/recorder.c b/trace/recorder.c
> new file mode 100644
> index 0000000000..cbc22ee2d5
> --- /dev/null
> +++ b/trace/recorder.c
> @@ -0,0 +1,22 @@
> +/*
> + * Recorder-based trace backend
> + *
> + * Copyright Red Hat 2020
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2. See
> + * the COPYING file in the top-level directory.
> + *
> + */
> +
> +#include "trace/recorder.h"
> +
> +RECORDER_CONSTRUCTOR
> +void recorder_trace_init(void)
> +{
> + recorder_trace_set(getenv("RECORDER_TRACES"));
> +
> + // Allow a dump in case we receive some unhandled signal
> + // For example, send USR2 to a hung process to get a dump
> + if (getenv("RECORDER_TRACES"))
> + recorder_dump_on_common_signals(0,0);
> +}
> diff --git a/trace/recorder.h b/trace/recorder.h
> new file mode 100644
> index 0000000000..00b11a2d2f
> --- /dev/null
> +++ b/trace/recorder.h
> @@ -0,0 +1,34 @@
> +/*
> + * Recorder-based trace backend
> + *
> + * Copyright Red Hat 2020
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2. See
> + * the COPYING file in the top-level directory.
> + *
> + */
> +
> +#ifndef TRACE_RECORDER_H
> +#define TRACE_RECORDER_H
> +
> +#include "qemu/osdep.h"
> +
> +#ifdef CONFIG_TRACE_RECORDER
> +
> +#include <recorder/recorder.h>
> +
> +extern void recorder_trace_init(void);
> +
> +#else
> +
> +// Disable recorder macros
> +#define RECORDER(Name, Size, Description)
> +#define RECORDER_DEFINE(Name, Size, Description)
> +#define RECORDER_DECLARE(Name)
> +#define RECORD(Name, ...)
> +#define record(Name, ...)
> +#define recorder_trace_init()
> +
> +#endif // CONFIG_TRACE_RECORDER
> +
> +#endif // TRACE_RECORDER_H
> diff --git a/util/module.c b/util/module.c
> index e48d9aacc0..2fa93561fe 100644
> --- a/util/module.c
> +++ b/util/module.c
> @@ -22,6 +22,10 @@
> #ifdef CONFIG_MODULE_UPGRADES
> #include "qemu-version.h"
> #endif
> +#ifdef CONFIG_TRACE_RECORDER
> +#include "trace/recorder.h"
> +#endif
> +
>
> typedef struct ModuleEntry
> {
> @@ -150,6 +154,10 @@ static int module_load_file(const char *fname)
> g_module_close(g_module);
> ret = -EINVAL;
> } else {
> +#ifdef CONFIG_TRACE_RECORDER
> + // New recorders may have been pulled in, activate them if necessary
> + recorder_trace_init();
> +#endif
> QTAILQ_FOREACH(e, &dso_init_list, node) {
> e->init();
> register_module_init(e->init, e->type);
> --
> 2.26.2
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
