Re: [PATCH RFC 04/11] perf script: Add API for filtering via dynamically loaded shared object

[Adrian Hunter <adrian.hunter@intel.com>]

On 22/06/21 9:32 pm, Arnaldo Carvalho de Melo wrote:
> Em Mon, Jun 21, 2021 at 06:05:07PM +0300, Adrian Hunter escreveu:
>> In some cases, users want to filter very large amounts of data (e.g. from
>> AUX area tracing like Intel PT) looking for something specific. While
>> scripting such as Python can be used, Python is 10 to 20 times slower than
>> C. So define a C API so that custom filters can be written and loaded.
> 
> Statically linking with perf would be even faster 8-) But yeah, I think
> its something useful, some notes below
> 
> A first question, can this be combined with pre-existing filters? I.e.
> 
>   perf script -C 0 --dlfilter file.so
> 
> ?

Thanks for looking at the patches.

Yes.  The filter_event() callback is called after internal filtering.
Patch 5 introduces filter_event_early() which is called before internal
filtering, but in either case all internal filtering is still done.

> 
> Also in the docs we can state that after these custom filters get
> polished and mature, it would be interesting to send them to be merged
> upstream, where they could even be statically linked with perf, if a
> profile session with it linked statically proves that.
> 
> Having a collection of such filters upstream we could then have
> a similar interface as for the script collection to describe filters,
> i.e. the .so file would have to have a description and perhaps a man
> page:
> 
> ⬢[acme@toolbox perf]$ perf script -l
> List of available trace scripts:
>   compaction-times [-h] [-u] [-p|-pv] [-t | [-m] [-fs] [-ms]] [pid|pid-range|comm-regex] display time taken by mm compaction
>   event_analyzing_sample               analyze all perf samples
>   export-to-postgresql [database name] [columns] [calls] export perf data to a postgresql database
>   export-to-sqlite [database name] [columns] [calls] export perf data to a sqlite3 database
>   failed-syscalls-by-pid [comm]        system-wide failed syscalls, by pid
>   flamegraph                           create flame graphs
>   futex-contention                     futext contention measurement
>   intel-pt-events                      print Intel PT Events including Power Events and PTWRITE
>   mem-phys-addr                        resolve physical address samples
>   net_dropmonitor                      display a table of dropped frames
>   netdev-times [tx] [rx] [dev=] [debug] display a process of packet and processing time
>   powerpc-hcalls
>   sched-migration                      sched migration overview
>   sctop [comm] [interval]              syscall top
>   stackcollapse                        produce callgraphs in short form for scripting use
>   syscall-counts-by-pid [comm]         system-wide syscall counts, by pid
>   syscall-counts [comm]                system-wide syscall counts
>   failed-syscalls [comm]               system-wide failed syscalls
>   rw-by-file <comm>                    r/w activity for a program, by file
>   rw-by-pid                            system-wide r/w activity
>   rwtop [interval]                     system-wide r/w top
>   wakeup-latency                       system-wide min/max/avg wakeup latency
> ⬢[acme@toolbox perf]$
> 
> I.e. some 'perf script --list-dlfilters'

Yes but we would also need some way to store and retrieve a 
description of the filter otherwise all we have is the file name.
I guess it could be another API function so the filter .so could
be loaded and the "const char* filter_description(const char **title)"
function called to get the description.

>  
>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
>> ---
>>  tools/perf/Documentation/perf-dlfilter.txt | 214 +++++++++++++
>>  tools/perf/Documentation/perf-script.txt   |   7 +-
>>  tools/perf/builtin-script.c                |  25 +-
>>  tools/perf/util/Build                      |   1 +
>>  tools/perf/util/dlfilter.c                 | 330 +++++++++++++++++++++
>>  tools/perf/util/dlfilter.h                 |  74 +++++
>>  tools/perf/util/perf_dlfilter.h            | 120 ++++++++
>>  7 files changed, 769 insertions(+), 2 deletions(-)
>>  create mode 100644 tools/perf/Documentation/perf-dlfilter.txt
>>  create mode 100644 tools/perf/util/dlfilter.c
>>  create mode 100644 tools/perf/util/dlfilter.h
>>  create mode 100644 tools/perf/util/perf_dlfilter.h
>>
>> diff --git a/tools/perf/Documentation/perf-dlfilter.txt b/tools/perf/Documentation/perf-dlfilter.txt
>> new file mode 100644
>> index 000000000000..d8f80998790f
>> --- /dev/null
>> +++ b/tools/perf/Documentation/perf-dlfilter.txt
>> @@ -0,0 +1,214 @@
>> +perf-dlfilter(1)
>> +================
>> +
>> +NAME
>> +----
>> +perf-dlfilter - Filter sample events using a dynamically loaded shared
>> +object file
>> +
>> +SYNOPSIS
>> +--------
>> +[verse]
>> +'perf script' [--dlfilter file.so ]
>> +
>> +DESCRIPTION
>> +-----------
>> +
>> +This option is used to process data through a custom filter provided by a
>> +dynamically loaded shared object file.
>> +
>> +API
>> +---
>> +
>> +The API for filtering consists of the following:
>> +
>> +[source,c]
>> +----
>> +#include <perf/perf_dlfilter.h>
>> +
>> +const struct perf_dlfilter_fns perf_dlfilter_fns;
>> +
>> +int start(void **data);
>> +int stop(void *data);
>> +int filter_event(void *data, const struct perf_dlfilter_sample *sample, void *ctx);
>> +----
>> +
>> +If implemented, 'start' will be called at the beginning, before any
>> +calls to 'filter_event' . Return 0 to indicate success,
>> +or return a negative error code. '*data' can be assigned for use by other
>> +functions.
>> +
>> +If implemented, 'stop' will be called at the end, after any calls to
>> +'filter_event'. Return 0 to indicate success, or
>> +return a negative error code. 'data' is set by 'start'.
>> +
>> +If implemented, 'filter_event' will be called for each sample event.
>> +Return 0 to keep the sample event, 1 to filter it out, or return a negative
>> +error code. 'data' is set by 'start'. 'ctx' is needed for calls to
>> +'perf_dlfilter_fns'.
>> +
>> +The perf_dlfilter_sample structure
>> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> +
>> +'filter_event' is passed a perf_dlfilter_sample
>> +structure, which contains the following fields:
>> +[source,c]
>> +----
>> +/*
>> + * perf sample event information (as per perf script and <linux/perf_event.h>)
>> + */
>> +struct perf_dlfilter_sample {
>> +	__u32 size; /* Size of this structure (for compatibility checking) */
> 
> There is a 4-byte hole here, 
> 
>> +	__u64 ip;
>> +	__s32 pid;
>> +	__s32 tid;
>> +	__u64 time;
>> +	__u64 addr;
>> +	__u64 id;
>> +	__u64 stream_id;
>> +	__u64 period;
>> +	__u64 weight;		/* Refer PERF_SAMPLE_WEIGHT_TYPE in <linux/perf_event.h> */
>> +	__u16 ins_lat;		/* Refer PERF_SAMPLE_WEIGHT_TYPE in <linux/perf_event.h> */
>> +	__u16 p_stage_cyc;	/* Refer PERF_SAMPLE_WEIGHT_TYPE in <linux/perf_event.h> */
> 
> Another
> 
> Can you move these last two __u16 to right after the 'size' field?

Sure

> 
>> +	__u64 transaction;	/* Refer PERF_SAMPLE_TRANSACTION in <linux/perf_event.h> */
>> +	__u64 insn_cnt;	/* For instructions-per-cycle (IPC) */
>> +	__u64 cyc_cnt;		/* For instructions-per-cycle (IPC) */
>> +	__s32 cpu;
>> +	__u32 flags;		/* Refer PERF_DLFILTER_FLAG_* above */
>> +	__u64 data_src;		/* Refer PERF_SAMPLE_DATA_SRC in <linux/perf_event.h> */
>> +	__u64 phys_addr;	/* Refer PERF_SAMPLE_PHYS_ADDR in <linux/perf_event.h> */
>> +	__u64 data_page_size;	/* Refer PERF_SAMPLE_DATA_PAGE_SIZE in <linux/perf_event.h> */
>> +	__u64 code_page_size;	/* Refer PERF_SAMPLE_CODE_PAGE_SIZE in <linux/perf_event.h> */
>> +	__u64 cgroup;		/* Refer PERF_SAMPLE_CGROUP in <linux/perf_event.h> */
>> +	__u8  cpumode;		/* Refer CPUMODE_MASK etc in <linux/perf_event.h> */
>> +	__u8  addr_correlates_sym; /* True => resolve_addr() can be called */
>> +	__u16 misc;		/* Refer perf_event_header in <linux/perf_event.h> */
>> +	__u32 raw_size;		/* Refer PERF_SAMPLE_RAW in <linux/perf_event.h> */
>> +	const void *raw_data;	/* Refer PERF_SAMPLE_RAW in <linux/perf_event.h> */
>> +	__u64 brstack_nr;	/* Number of brstack entries */
>> +	const struct perf_branch_entry *brstack; /* Refer <linux/perf_event.h> */
>> +	__u64 raw_callchain_nr;	/* Number of raw_callchain entries */
>> +	const __u64 *raw_callchain; /* Refer <linux/perf_event.h> */
>> +	const char *event;
>> +};
>> +----
>> +
>> +The perf_dlfilter_fns structure
>> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> +
>> +The 'perf_dlfilter_fns' structure is populated with function pointers when the
>> +file is loaded. The functions can be called by 'filter_event'.
>> +
>> +[source,c]
>> +----
>> +struct perf_dlfilter_fns {
>> +	const struct perf_dlfilter_al *(*resolve_ip)(void *ctx);
>> +	const struct perf_dlfilter_al *(*resolve_addr)(void *ctx);
>> +	void *(*reserved[126])(void *);
>> +};
>> +----
>> +
>> +'resolve_ip' returns information about ip.
>> +
>> +'resolve_addr' returns information about addr (if addr_correlates_sym).
>> +
>> +The perf_dlfilter_al structure
>> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> +
>> +The 'perf_dlfilter_al' structure contains information about an address.
>> +
>> +[source,c]
>> +----
>> +/*
>> + * Address location (as per perf script)
>> + */
>> +struct perf_dlfilter_al {
>> +	__u32 size; /* Size of this structure (for compatibility checking) */
>> +	__u32 symoff;
>> +	const char *sym;
>> +	__u64 addr; /* Mapped address (from dso) */
>> +	__u64 sym_start;
>> +	__u64 sym_end;
>> +	const char *dso;
>> +	__u8  sym_binding; /* STB_LOCAL, STB_GLOBAL or STB_WEAK, refer <elf.h> */
>> +	__u8  is_64_bit; /* Only valid if dso is not NULL */
>> +	__u8  is_kernel_ip; /* True if in kernel space */
>> +	__u32 buildid_size;
>> +	__u8 *buildid;
>> +	/* Below members are only populated by resolve_ip() */
>> +	__u8 filtered; /* true if this sample event will be filtered out */
>> +	const char *comm;
>> +};
>> +----
>> +
>> +perf_dlfilter_sample flags
>> +~~~~~~~~~~~~~~~~~~~~~~~~~~
>> +
>> +The 'flags' member of 'perf_dlfilter_sample' corresponds with the flags field
>> +of perf script. The bits of the flags are as follows:
>> +
>> +[source,c]
>> +----
>> +/* Definitions for perf_dlfilter_sample flags */
>> +enum {
>> +	PERF_DLFILTER_FLAG_BRANCH	= 1ULL << 0,
>> +	PERF_DLFILTER_FLAG_CALL		= 1ULL << 1,
>> +	PERF_DLFILTER_FLAG_RETURN	= 1ULL << 2,
>> +	PERF_DLFILTER_FLAG_CONDITIONAL	= 1ULL << 3,
>> +	PERF_DLFILTER_FLAG_SYSCALLRET	= 1ULL << 4,
>> +	PERF_DLFILTER_FLAG_ASYNC	= 1ULL << 5,
>> +	PERF_DLFILTER_FLAG_INTERRUPT	= 1ULL << 6,
>> +	PERF_DLFILTER_FLAG_TX_ABORT	= 1ULL << 7,
>> +	PERF_DLFILTER_FLAG_TRACE_BEGIN	= 1ULL << 8,
>> +	PERF_DLFILTER_FLAG_TRACE_END	= 1ULL << 9,
>> +	PERF_DLFILTER_FLAG_IN_TX	= 1ULL << 10,
>> +	PERF_DLFILTER_FLAG_VMENTRY	= 1ULL << 11,
>> +	PERF_DLFILTER_FLAG_VMEXIT	= 1ULL << 12,
>> +};
>> +----
>> +
>> +EXAMPLE
>> +-------
>> +
>> +Filter out everything except branches from "foo" to "bar":
>> +
>> +[source,c]
>> +----
>> +#include <perf/perf_dlfilter.h>
>> +#include <string.h>
>> +
>> +const struct perf_dlfilter_fns perf_dlfilter_fns;
>> +
>> +int filter_event(void *data, const struct perf_dlfilter_sample *sample, void *ctx)
>> +{
>> +	const struct perf_dlfilter_al *al;
>> +	const struct perf_dlfilter_al *addr_al;
>> +
>> +	if (!sample->ip || !sample->addr_correlates_sym)
>> +		return 1;
>> +
>> +	al = perf_dlfilter_fns.resolve_ip(ctx);
>> +	if (!al || !al->sym || strcmp(al->sym, "foo"))
>> +		return 1;
>> +
>> +	addr_al = perf_dlfilter_fns.resolve_addr(ctx);
>> +	if (!addr_al || !addr_al->sym || strcmp(addr_al->sym, "bar"))
>> +		return 1;
>> +
>> +	return 0;
>> +}
>> +----
>> +
>> +To build the shared object, assuming perf has been installed for the local user
>> +i.e. perf_dlfilter.h is in ~/include/perf :
>> +
>> +	gcc -c -I ~/include -fpic dlfilter-example.c
>> +	gcc -shared -o dlfilter-example.so dlfilter-example.o
>> +
>> +To use the filter with perf script:
>> +
>> +	perf script --dlfilter ./dlfilter-example.so
>> +
>> +SEE ALSO
>> +--------
>> +linkperf:perf-script[1]
>> diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
>> index 48a5f5b26dd4..2306c81b606b 100644
>> --- a/tools/perf/Documentation/perf-script.txt
>> +++ b/tools/perf/Documentation/perf-script.txt
>> @@ -98,6 +98,10 @@ OPTIONS
>>          Generate perf-script.[ext] starter script for given language,
>>          using current perf.data.
>>  
>> +--dlfilter=<file>::
>> +	Filter sample events using the given shared object file.
>> +	Refer linkperf:perf-dlfilter[1]
>> +
>>  -a::
>>          Force system-wide collection.  Scripts run without a <command>
>>          normally use -a by default, while scripts run with a <command>
>> @@ -483,4 +487,5 @@ include::itrace.txt[]
>>  SEE ALSO
>>  --------
>>  linkperf:perf-record[1], linkperf:perf-script-perl[1],
>> -linkperf:perf-script-python[1], linkperf:perf-intel-pt[1]
>> +linkperf:perf-script-python[1], linkperf:perf-intel-pt[1],
>> +linkperf:perf-dlfilter[1]
>> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
>> index d2771a997e26..aaf2922643a0 100644
>> --- a/tools/perf/builtin-script.c
>> +++ b/tools/perf/builtin-script.c
>> @@ -55,6 +55,7 @@
>>  #include <subcmd/pager.h>
>>  #include <perf/evlist.h>
>>  #include <linux/err.h>
>> +#include "util/dlfilter.h"
>>  #include "util/record.h"
>>  #include "util/util.h"
>>  #include "perf.h"
>> @@ -79,6 +80,7 @@ static DECLARE_BITMAP(cpu_bitmap, MAX_NR_CPUS);
>>  static struct perf_stat_config	stat_config;
>>  static int			max_blocks;
>>  static bool			native_arch;
>> +static struct dlfilter		*dlfilter;
>>  
>>  unsigned int scripting_max_stack = PERF_MAX_STACK_DEPTH;
>>  
>> @@ -2175,6 +2177,7 @@ static int process_sample_event(struct perf_tool *tool,
>>  	struct perf_script *scr = container_of(tool, struct perf_script, tool);
>>  	struct addr_location al;
>>  	struct addr_location addr_al;
>> +	int ret = 0;
>>  
>>  	if (perf_time__ranges_skip_sample(scr->ptime_range, scr->range_num,
>>  					  sample->time)) {
>> @@ -2213,6 +2216,13 @@ static int process_sample_event(struct perf_tool *tool,
>>  	if (evswitch__discard(&scr->evswitch, evsel))
>>  		goto out_put;
>>  
>> +	ret = dlfilter__filter_event(dlfilter, event, sample, evsel, machine, &al, &addr_al);
>> +	if (ret) {
>> +		if (ret > 0)
>> +			ret = 0;
>> +		goto out_put;
>> +	}
>> +
>>  	if (scripting_ops) {
>>  		struct addr_location *addr_al_ptr = NULL;
>>  
>> @@ -2229,7 +2239,7 @@ static int process_sample_event(struct perf_tool *tool,
>>  
>>  out_put:
>>  	addr_location__put(&al);
>> -	return 0;
>> +	return ret;
>>  }
>>  
>>  static int process_attr(struct perf_tool *tool, union perf_event *event,
>> @@ -3568,6 +3578,7 @@ int cmd_script(int argc, const char **argv)
>>  	};
>>  	struct utsname uts;
>>  	char *script_path = NULL;
>> +	const char *dlfilter_file = NULL;
>>  	const char **__argv;
>>  	int i, j, err = 0;
>>  	struct perf_script script = {
>> @@ -3615,6 +3626,7 @@ int cmd_script(int argc, const char **argv)
>>  		     parse_scriptname),
>>  	OPT_STRING('g', "gen-script", &generate_script_lang, "lang",
>>  		   "generate perf-script.xx script in specified language"),
>> +	OPT_STRING(0, "dlfilter", &dlfilter_file, "file", "filter .so file name"),
>>  	OPT_STRING('i', "input", &input_name, "file", "input file name"),
>>  	OPT_BOOLEAN('d', "debug-mode", &debug_mode,
>>  		   "do various checks like samples ordering and lost events"),
>> @@ -3933,6 +3945,12 @@ int cmd_script(int argc, const char **argv)
>>  		exit(-1);
>>  	}
>>  
>> +	if (dlfilter_file) {
>> +		dlfilter = dlfilter__new(dlfilter_file);
>> +		if (!dlfilter)
>> +			return -1;
>> +	}
>> +
>>  	if (!script_name) {
>>  		setup_pager();
>>  		use_browser = 0;
>> @@ -4032,6 +4050,10 @@ int cmd_script(int argc, const char **argv)
>>  		goto out_delete;
>>  	}
>>  
>> +	err = dlfilter__start(dlfilter, session);
>> +	if (err)
>> +		goto out_delete;
>> +
>>  	if (script_name) {
>>  		err = scripting_ops->start_script(script_name, argc, argv, session);
>>  		if (err)
>> @@ -4081,6 +4103,7 @@ int cmd_script(int argc, const char **argv)
>>  
>>  	if (script_started)
>>  		cleanup_scripting();
>> +	dlfilter__cleanup(dlfilter);
>>  out:
>>  	return err;
>>  }
>> diff --git a/tools/perf/util/Build b/tools/perf/util/Build
>> index 95e15d1035ab..1a909b53dc15 100644
>> --- a/tools/perf/util/Build
>> +++ b/tools/perf/util/Build
>> @@ -126,6 +126,7 @@ perf-y += parse-regs-options.o
>>  perf-y += parse-sublevel-options.o
>>  perf-y += term.o
>>  perf-y += help-unknown-cmd.o
>> +perf-y += dlfilter.o
>>  perf-y += mem-events.o
>>  perf-y += vsprintf.o
>>  perf-y += units.o
>> diff --git a/tools/perf/util/dlfilter.c b/tools/perf/util/dlfilter.c
>> new file mode 100644
>> index 000000000000..15cb9de13a4b
>> --- /dev/null
>> +++ b/tools/perf/util/dlfilter.c
>> @@ -0,0 +1,330 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * dlfilter.c: Interface to perf script --dlfilter shared object
>> + * Copyright (c) 2021, Intel Corporation.
>> + */
>> +#include <dlfcn.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +#include <linux/zalloc.h>
>> +#include <linux/build_bug.h>
>> +
>> +#include "debug.h"
>> +#include "event.h"
>> +#include "evsel.h"
>> +#include "dso.h"
>> +#include "map.h"
>> +#include "thread.h"
>> +#include "symbol.h"
>> +#include "dlfilter.h"
>> +#include "perf_dlfilter.h"
>> +
>> +static void al_to_d_al(struct addr_location *al, struct perf_dlfilter_al *d_al)
>> +{
>> +	struct symbol *sym = al->sym;
>> +
>> +	d_al->size = sizeof(*d_al);
>> +	if (al->map) {
>> +		struct dso *dso = al->map->dso;
>> +
>> +		if (symbol_conf.show_kernel_path && dso->long_name)
>> +			d_al->dso = dso->long_name;
>> +		else
>> +			d_al->dso = dso->name;
>> +		d_al->is_64_bit = dso->is_64_bit;
>> +		d_al->buildid_size = dso->bid.size;
>> +		d_al->buildid = dso->bid.data;
>> +	} else {
>> +		d_al->dso = NULL;
>> +		d_al->is_64_bit = 0;
>> +		d_al->buildid_size = 0;
>> +		d_al->buildid = NULL;
>> +	}
>> +	if (sym) {
>> +		d_al->sym = sym->name;
>> +		d_al->sym_start = sym->start;
>> +		d_al->sym_end = sym->end;
>> +		if (al->addr < sym->end)
>> +			d_al->symoff = al->addr - sym->start;
>> +		else
>> +			d_al->symoff = al->addr - al->map->start - sym->start;
>> +		d_al->sym_binding = sym->binding;
>> +	} else {
>> +		d_al->sym = NULL;
>> +		d_al->sym_start = 0;
>> +		d_al->sym_end = 0;
>> +		d_al->symoff = 0;
>> +		d_al->sym_binding = 0;
>> +	}
>> +	d_al->addr = al->addr;
>> +	d_al->comm = NULL;
>> +	d_al->filtered = 0;
>> +}
>> +
>> +static struct addr_location *get_al(struct dlfilter *d)
>> +{
>> +	struct addr_location *al = d->al;
>> +
>> +	if (!al->thread && machine__resolve(d->machine, al, d->sample) < 0)
>> +		return NULL;
>> +	return al;
>> +}
>> +
>> +static struct thread *get_thread(struct dlfilter *d)
>> +{
>> +	struct addr_location *al = get_al(d);
>> +
>> +	return al ? al->thread : NULL;
>> +}
>> +
>> +static const struct perf_dlfilter_al *dlfilter__resolve_ip(void *ctx)
>> +{
>> +	struct dlfilter *d = (struct dlfilter *)ctx;
>> +	struct perf_dlfilter_al *d_al = d->d_ip_al;
>> +	struct addr_location *al;
>> +
>> +	if (!d->ctx_valid)
>> +		return NULL;
>> +
>> +	/* 'size' is also used to indicate already initialized */
>> +	if (d_al->size)
>> +		return d_al;
>> +
>> +	al = get_al(d);
>> +	if (!al)
>> +		return NULL;
>> +
>> +	al_to_d_al(al, d_al);
>> +
>> +	d_al->is_kernel_ip = machine__kernel_ip(d->machine, d->sample->ip);
>> +	d_al->comm = al->thread ? thread__comm_str(al->thread) : ":-1";
>> +	d_al->filtered = al->filtered;
>> +
>> +	return d_al;
>> +}
>> +
>> +static const struct perf_dlfilter_al *dlfilter__resolve_addr(void *ctx)
>> +{
>> +	struct dlfilter *d = (struct dlfilter *)ctx;
>> +	struct perf_dlfilter_al *d_addr_al = d->d_addr_al;
>> +	struct addr_location *addr_al = d->addr_al;
>> +
>> +	if (!d->ctx_valid || !d->d_sample->addr_correlates_sym)
>> +		return NULL;
>> +
>> +	/* 'size' is also used to indicate already initialized */
>> +	if (d_addr_al->size)
>> +		return d_addr_al;
>> +
>> +	if (!addr_al->thread) {
>> +		struct thread *thread = get_thread(d);
>> +
>> +		if (!thread)
>> +			return NULL;
>> +		thread__resolve(thread, addr_al, d->sample);
>> +	}
>> +
>> +	al_to_d_al(addr_al, d_addr_al);
>> +
>> +	d_addr_al->is_kernel_ip = machine__kernel_ip(d->machine, d->sample->addr);
>> +
>> +	return d_addr_al;
>> +}
>> +
>> +static const struct perf_dlfilter_fns perf_dlfilter_fns = {
>> +	.resolve_ip      = dlfilter__resolve_ip,
>> +	.resolve_addr    = dlfilter__resolve_addr,
>> +};
>> +
>> +#define CHECK_FLAG(x) BUILD_BUG_ON((u64)PERF_DLFILTER_FLAG_ ## x != (u64)PERF_IP_FLAG_ ## x)
>> +
>> +static int dlfilter__init(struct dlfilter *d, const char *file)
>> +{
>> +	CHECK_FLAG(BRANCH);
>> +	CHECK_FLAG(CALL);
>> +	CHECK_FLAG(RETURN);
>> +	CHECK_FLAG(CONDITIONAL);
>> +	CHECK_FLAG(SYSCALLRET);
>> +	CHECK_FLAG(ASYNC);
>> +	CHECK_FLAG(INTERRUPT);
>> +	CHECK_FLAG(TX_ABORT);
>> +	CHECK_FLAG(TRACE_BEGIN);
>> +	CHECK_FLAG(TRACE_END);
>> +	CHECK_FLAG(IN_TX);
>> +	CHECK_FLAG(VMENTRY);
>> +	CHECK_FLAG(VMEXIT);
>> +
>> +	memset(d, 0, sizeof(*d));
>> +	d->file = strdup(file);
>> +	if (!d->file)
>> +		return -1;
>> +	return 0;
>> +}
>> +
>> +static void dlfilter__exit(struct dlfilter *d)
>> +{
>> +	zfree(&d->file);
>> +}
>> +
>> +static int dlfilter__open(struct dlfilter *d)
>> +{
>> +	d->handle = dlopen(d->file, RTLD_NOW);
>> +	if (!d->handle) {
>> +		pr_err("dlopen failed for: '%s'\n", d->file);
>> +		return -1;
>> +	}
>> +	d->start = dlsym(d->handle, "start");
>> +	d->filter_event = dlsym(d->handle, "filter_event");
>> +	d->stop = dlsym(d->handle, "stop");
>> +	d->fns = dlsym(d->handle, "perf_dlfilter_fns");
>> +	if (d->fns)
>> +		memcpy(d->fns, &perf_dlfilter_fns, sizeof(struct perf_dlfilter_fns));
>> +	return 0;
>> +}
>> +
>> +static int dlfilter__close(struct dlfilter *d)
>> +{
>> +	return dlclose(d->handle);
>> +}
>> +
>> +struct dlfilter *dlfilter__new(const char *file)
>> +{
>> +	struct dlfilter *d = malloc(sizeof(*d));
>> +
>> +	if (!d)
>> +		return NULL;
>> +
>> +	if (dlfilter__init(d, file))
>> +		goto err_free;
>> +
>> +	if (dlfilter__open(d))
>> +		goto err_exit;
>> +
>> +	return d;
>> +
>> +err_exit:
>> +	dlfilter__exit(d);
>> +err_free:
>> +	free(d);
>> +	return NULL;
>> +}
>> +
>> +static void dlfilter__free(struct dlfilter *d)
>> +{
>> +	if (d) {
>> +		dlfilter__exit(d);
>> +		free(d);
>> +	}
>> +}
>> +
>> +int dlfilter__start(struct dlfilter *d, struct perf_session *session)
>> +{
>> +	if (d) {
>> +		d->session = session;
>> +		if (d->start)
>> +			return d->start(&d->data);
>> +	}
>> +	return 0;
>> +}
>> +
>> +static int dlfilter__stop(struct dlfilter *d)
>> +{
>> +	if (d && d->stop)
>> +		return d->stop(d->data);
>> +	return 0;
>> +}
>> +
>> +void dlfilter__cleanup(struct dlfilter *d)
>> +{
>> +	if (d) {
>> +		dlfilter__stop(d);
>> +		dlfilter__close(d);
>> +		dlfilter__free(d);
>> +	}
>> +}
>> +
>> +#define ASSIGN(x) d_sample.x = sample->x
>> +
>> +int dlfilter__do_filter_event(struct dlfilter *d,
>> +			      union perf_event *event,
>> +			      struct perf_sample *sample,
>> +			      struct evsel *evsel,
>> +			      struct machine *machine,
>> +			      struct addr_location *al,
>> +			      struct addr_location *addr_al)
>> +{
>> +	struct perf_dlfilter_sample d_sample;
>> +	struct perf_dlfilter_al d_ip_al;
>> +	struct perf_dlfilter_al d_addr_al;
>> +	int ret;
>> +
>> +	d->event       = event;
>> +	d->sample      = sample;
>> +	d->evsel       = evsel;
>> +	d->machine     = machine;
>> +	d->al          = al;
>> +	d->addr_al     = addr_al;
>> +	d->d_sample    = &d_sample;
>> +	d->d_ip_al     = &d_ip_al;
>> +	d->d_addr_al   = &d_addr_al;
>> +
>> +	d_sample.size  = sizeof(d_sample);
>> +	d_ip_al.size   = 0; /* To indicate d_ip_al is not initialized */
>> +	d_addr_al.size = 0; /* To indicate d_addr_al is not initialized */
>> +
>> +	ASSIGN(ip);
>> +	ASSIGN(pid);
>> +	ASSIGN(tid);
>> +	ASSIGN(time);
>> +	ASSIGN(addr);
>> +	ASSIGN(id);
>> +	ASSIGN(stream_id);
>> +	ASSIGN(period);
>> +	ASSIGN(weight);
>> +	ASSIGN(ins_lat);
>> +	ASSIGN(p_stage_cyc);
>> +	ASSIGN(transaction);
>> +	ASSIGN(insn_cnt);
>> +	ASSIGN(cyc_cnt);
>> +	ASSIGN(cpu);
>> +	ASSIGN(flags);
>> +	ASSIGN(data_src);
>> +	ASSIGN(phys_addr);
>> +	ASSIGN(data_page_size);
>> +	ASSIGN(code_page_size);
>> +	ASSIGN(cgroup);
>> +	ASSIGN(cpumode);
>> +	ASSIGN(misc);
>> +	ASSIGN(raw_size);
>> +	ASSIGN(raw_data);
>> +
>> +	if (sample->branch_stack) {
>> +		d_sample.brstack_nr = sample->branch_stack->nr;
>> +		d_sample.brstack = (struct perf_branch_entry *)perf_sample__branch_entries(sample);
>> +	} else {
>> +		d_sample.brstack_nr = 0;
>> +		d_sample.brstack = NULL;
>> +	}
>> +
>> +	if (sample->callchain) {
>> +		d_sample.raw_callchain_nr = sample->callchain->nr;
>> +		d_sample.raw_callchain = (__u64 *)sample->callchain->ips;
>> +	} else {
>> +		d_sample.raw_callchain_nr = 0;
>> +		d_sample.raw_callchain = NULL;
>> +	}
>> +
>> +	d_sample.addr_correlates_sym =
>> +		(evsel->core.attr.sample_type & PERF_SAMPLE_ADDR) &&
>> +		sample_addr_correlates_sym(&evsel->core.attr);
>> +
>> +	d_sample.event = evsel__name(evsel);
>> +
>> +	d->ctx_valid = true;
>> +
>> +	ret = d->filter_event(d->data, &d_sample, d);
>> +
>> +	d->ctx_valid = false;
>> +
>> +	return ret;
>> +}
>> diff --git a/tools/perf/util/dlfilter.h b/tools/perf/util/dlfilter.h
>> new file mode 100644
>> index 000000000000..671e2d3d5a06
>> --- /dev/null
>> +++ b/tools/perf/util/dlfilter.h
>> @@ -0,0 +1,74 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * dlfilter.h: Interface to perf script --dlfilter shared object
>> + * Copyright (c) 2021, Intel Corporation.
>> + */
>> +
>> +#ifndef PERF_UTIL_DLFILTER_H
>> +#define PERF_UTIL_DLFILTER_H
>> +
>> +struct perf_session;
>> +union  perf_event;
>> +struct perf_sample;
>> +struct evsel;
>> +struct machine;
>> +struct addr_location;
>> +struct perf_dlfilter_fns;
>> +struct perf_dlfilter_sample;
>> +struct perf_dlfilter_al;
>> +
>> +struct dlfilter {
>> +	char				*file;
>> +	void				*handle;
>> +	void				*data;
>> +	struct perf_session		*session;
>> +	bool				ctx_valid;
>> +
>> +	union perf_event		*event;
>> +	struct perf_sample		*sample;
>> +	struct evsel			*evsel;
>> +	struct machine			*machine;
>> +	struct addr_location		*al;
>> +	struct addr_location		*addr_al;
>> +	struct perf_dlfilter_sample	*d_sample;
>> +	struct perf_dlfilter_al		*d_ip_al;
>> +	struct perf_dlfilter_al		*d_addr_al;
>> +
>> +	int (*start)(void **data);
>> +	int (*stop)(void *data);
>> +
>> +	int (*filter_event)(void *data,
>> +			    const struct perf_dlfilter_sample *sample,
>> +			    void *ctx);
>> +
>> +	struct perf_dlfilter_fns *fns;
>> +};
>> +
>> +struct dlfilter *dlfilter__new(const char *file);
>> +
>> +int dlfilter__start(struct dlfilter *d, struct perf_session *session);
>> +
>> +int dlfilter__do_filter_event(struct dlfilter *d,
>> +			      union perf_event *event,
>> +			      struct perf_sample *sample,
>> +			      struct evsel *evsel,
>> +			      struct machine *machine,
>> +			      struct addr_location *al,
>> +			      struct addr_location *addr_al);
>> +
>> +void dlfilter__cleanup(struct dlfilter *d);
>> +
>> +static inline int dlfilter__filter_event(struct dlfilter *d,
>> +					 union perf_event *event,
>> +					 struct perf_sample *sample,
>> +					 struct evsel *evsel,
>> +					 struct machine *machine,
>> +					 struct addr_location *al,
>> +					 struct addr_location *addr_al)
>> +{
>> +	if (!d || !d->filter_event)
>> +		return 0;
>> +	return dlfilter__do_filter_event(d, event, sample, evsel, machine, al, addr_al);
>> +}
>> +
>> +#endif
>> diff --git a/tools/perf/util/perf_dlfilter.h b/tools/perf/util/perf_dlfilter.h
>> new file mode 100644
>> index 000000000000..132f833f0a0b
>> --- /dev/null
>> +++ b/tools/perf/util/perf_dlfilter.h
>> @@ -0,0 +1,120 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * perf_dlfilter.h: API for perf --dlfilter shared object
>> + * Copyright (c) 2021, Intel Corporation.
>> + */
>> +#ifndef _LINUX_PERF_DLFILTER_H
>> +#define _LINUX_PERF_DLFILTER_H
>> +
>> +#include <linux/perf_event.h>
>> +#include <linux/types.h>
>> +
>> +/* Definitions for perf_dlfilter_sample flags */
>> +enum {
>> +	PERF_DLFILTER_FLAG_BRANCH	= 1ULL << 0,
>> +	PERF_DLFILTER_FLAG_CALL		= 1ULL << 1,
>> +	PERF_DLFILTER_FLAG_RETURN	= 1ULL << 2,
>> +	PERF_DLFILTER_FLAG_CONDITIONAL	= 1ULL << 3,
>> +	PERF_DLFILTER_FLAG_SYSCALLRET	= 1ULL << 4,
>> +	PERF_DLFILTER_FLAG_ASYNC	= 1ULL << 5,
>> +	PERF_DLFILTER_FLAG_INTERRUPT	= 1ULL << 6,
>> +	PERF_DLFILTER_FLAG_TX_ABORT	= 1ULL << 7,
>> +	PERF_DLFILTER_FLAG_TRACE_BEGIN	= 1ULL << 8,
>> +	PERF_DLFILTER_FLAG_TRACE_END	= 1ULL << 9,
>> +	PERF_DLFILTER_FLAG_IN_TX	= 1ULL << 10,
>> +	PERF_DLFILTER_FLAG_VMENTRY	= 1ULL << 11,
>> +	PERF_DLFILTER_FLAG_VMEXIT	= 1ULL << 12,
>> +};
>> +
>> +/*
>> + * perf sample event information (as per perf script and <linux/perf_event.h>)
>> + */
>> +struct perf_dlfilter_sample {
>> +	__u32 size; /* Size of this structure (for compatibility checking) */
>> +	__u64 ip;
>> +	__s32 pid;
>> +	__s32 tid;
>> +	__u64 time;
>> +	__u64 addr;
>> +	__u64 id;
>> +	__u64 stream_id;
>> +	__u64 period;
>> +	__u64 weight;		/* Refer PERF_SAMPLE_WEIGHT_TYPE in <linux/perf_event.h> */
>> +	__u16 ins_lat;		/* Refer PERF_SAMPLE_WEIGHT_TYPE in <linux/perf_event.h> */
>> +	__u16 p_stage_cyc;	/* Refer PERF_SAMPLE_WEIGHT_TYPE in <linux/perf_event.h> */
>> +	__u64 transaction;	/* Refer PERF_SAMPLE_TRANSACTION in <linux/perf_event.h> */
>> +	__u64 insn_cnt;	/* For instructions-per-cycle (IPC) */
>> +	__u64 cyc_cnt;		/* For instructions-per-cycle (IPC) */
>> +	__s32 cpu;
>> +	__u32 flags;		/* Refer PERF_DLFILTER_FLAG_* above */
>> +	__u64 data_src;		/* Refer PERF_SAMPLE_DATA_SRC in <linux/perf_event.h> */
>> +	__u64 phys_addr;	/* Refer PERF_SAMPLE_PHYS_ADDR in <linux/perf_event.h> */
>> +	__u64 data_page_size;	/* Refer PERF_SAMPLE_DATA_PAGE_SIZE in <linux/perf_event.h> */
>> +	__u64 code_page_size;	/* Refer PERF_SAMPLE_CODE_PAGE_SIZE in <linux/perf_event.h> */
>> +	__u64 cgroup;		/* Refer PERF_SAMPLE_CGROUP in <linux/perf_event.h> */
>> +	__u8  cpumode;		/* Refer CPUMODE_MASK etc in <linux/perf_event.h> */
>> +	__u8  addr_correlates_sym; /* True => resolve_addr() can be called */
>> +	__u16 misc;		/* Refer perf_event_header in <linux/perf_event.h> */
>> +	__u32 raw_size;		/* Refer PERF_SAMPLE_RAW in <linux/perf_event.h> */
>> +	const void *raw_data;	/* Refer PERF_SAMPLE_RAW in <linux/perf_event.h> */
>> +	__u64 brstack_nr;	/* Number of brstack entries */
>> +	const struct perf_branch_entry *brstack; /* Refer <linux/perf_event.h> */
>> +	__u64 raw_callchain_nr;	/* Number of raw_callchain entries */
>> +	const __u64 *raw_callchain; /* Refer <linux/perf_event.h> */
>> +	const char *event;
>> +};
>> +
>> +/*
>> + * Address location (as per perf script)
>> + */
>> +struct perf_dlfilter_al {
>> +	__u32 size; /* Size of this structure (for compatibility checking) */
>> +	__u32 symoff;
>> +	const char *sym;
>> +	__u64 addr; /* Mapped address (from dso) */
>> +	__u64 sym_start;
>> +	__u64 sym_end;
>> +	const char *dso;
>> +	__u8  sym_binding; /* STB_LOCAL, STB_GLOBAL or STB_WEAK, refer <elf.h> */
>> +	__u8  is_64_bit; /* Only valid if dso is not NULL */
>> +	__u8  is_kernel_ip; /* True if in kernel space */
>> +	__u32 buildid_size;
>> +	__u8 *buildid;
>> +	/* Below members are only populated by resolve_ip() */
>> +	__u8 filtered; /* True if this sample event will be filtered out */
>> +	const char *comm;
>> +};
>> +
>> +struct perf_dlfilter_fns {
>> +	/* Return information about ip */
>> +	const struct perf_dlfilter_al *(*resolve_ip)(void *ctx);
>> +	/* Return information about addr (if addr_correlates_sym) */
>> +	const struct perf_dlfilter_al *(*resolve_addr)(void *ctx);
>> +	/* Reserved */
>> +	void *(*reserved[126])(void *);
>> +};
>> +
>> +/*
>> + * If implemented, 'start' will be called at the beginning,
>> + * before any calls to 'filter_event'. Return 0 to indicate success,
>> + * or return a negative error code. '*data' can be assigned for use
>> + * by other functions.
>> + */
>> +int start(void **data);
>> +
>> +/*
>> + * If implemented, 'stop' will be called at the end,
>> + * after any calls to 'filter_event'. Return 0 to indicate success, or
>> + * return a negative error code. 'data' is set by start().
>> + */
>> +int stop(void *data);
>> +
>> +/*
>> + * If implemented, 'filter_event' will be called for each sample
>> + * event. Return 0 to keep the sample event, 1 to filter it out, or
>> + * return a negative error code. 'data' is set by start(). 'ctx' is
>> + * needed for calls to perf_dlfilter_fns.
>> + */
>> +int filter_event(void *data, const struct perf_dlfilter_sample *sample, void *ctx);
>> +
>> +#endif
>> -- 
>> 2.17.1
>>
>