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Date: Fri, 20 Sep 2019 21:00:38 +0800
From: "Jin, Yao" <yao.jin@...ux.intel.com>
To: acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
mingo@...hat.com, alexander.shishkin@...ux.intel.com
Cc: Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v7] perf diff: Report noisy for cycles diff
Hi,
Can this patch be accepted?
Thanks
Jin Yao
On 9/3/2019 10:03 AM, Jin Yao wrote:
> This patch prints the stddev and hist for the cycles diff of
> program block. It can help us to understand if the cycles
> is noisy or not.
>
> This patch is inspired by Andi Kleen's patch
> https://lwn.net/Articles/600471/
>
> We create new option '--cycles-hist'.
>
> Example:
>
> perf record -b ./div
> perf record -b ./div
> perf diff -c cycles
>
> # Baseline [Program Block Range] Cycles Diff Shared Object Symbol
> # ........ ...................................................................... ................. ............................
> #
> 46.72% [div.c:40 -> div.c:40] 0 div [.] main
> 46.72% [div.c:42 -> div.c:44] 0 div [.] main
> 46.72% [div.c:42 -> div.c:39] 0 div [.] main
> 20.54% [random_r.c:357 -> random_r.c:394] 1 libc-2.27.so [.] __random_r
> 20.54% [random_r.c:357 -> random_r.c:380] 0 libc-2.27.so [.] __random_r
> 20.54% [random_r.c:388 -> random_r.c:388] 0 libc-2.27.so [.] __random_r
> 20.54% [random_r.c:388 -> random_r.c:391] 0 libc-2.27.so [.] __random_r
> 17.04% [random.c:288 -> random.c:291] 0 libc-2.27.so [.] __random
> 17.04% [random.c:291 -> random.c:291] 0 libc-2.27.so [.] __random
> 17.04% [random.c:293 -> random.c:293] 0 libc-2.27.so [.] __random
> 17.04% [random.c:295 -> random.c:295] 0 libc-2.27.so [.] __random
> 17.04% [random.c:295 -> random.c:295] 0 libc-2.27.so [.] __random
> 17.04% [random.c:298 -> random.c:298] 0 libc-2.27.so [.] __random
> 8.40% [div.c:22 -> div.c:25] 0 div [.] compute_flag
> 8.40% [div.c:27 -> div.c:28] 0 div [.] compute_flag
> 5.14% [rand.c:26 -> rand.c:27] 0 libc-2.27.so [.] rand
> 5.14% [rand.c:28 -> rand.c:28] 0 libc-2.27.so [.] rand
> 2.15% [rand@...+0 -> rand@...+0] 0 div [.] rand@plt
> 0.00% [kernel.kallsyms] [k] __x86_indirect_thunk_rax
> 0.00% [do_mmap+714 -> do_mmap+732] -10 [kernel.kallsyms] [k] do_mmap
> 0.00% [do_mmap+737 -> do_mmap+765] 1 [kernel.kallsyms] [k] do_mmap
> 0.00% [do_mmap+262 -> do_mmap+299] 0 [kernel.kallsyms] [k] do_mmap
> 0.00% [__x86_indirect_thunk_r15+0 -> __x86_indirect_thunk_r15+0] 7 [kernel.kallsyms] [k] __x86_indirect_thunk_r15
> 0.00% [native_sched_clock+0 -> native_sched_clock+119] -1 [kernel.kallsyms] [k] native_sched_clock
> 0.00% [native_write_msr+0 -> native_write_msr+16] -13 [kernel.kallsyms] [k] native_write_msr
>
> When we enable the option '--cycles-hist', the output is
>
> perf diff -c cycles --cycles-hist
>
> # Baseline [Program Block Range] Cycles Diff stddev/Hist Shared Object Symbol
> # ........ ...................................................................... ................. ................. ............................
> #
> 46.72% [div.c:40 -> div.c:40] 0 ± 37.8% ▁█▁▁██▁█ div [.] main
> 46.72% [div.c:42 -> div.c:44] 0 ± 49.4% ▁▁▂█▂▂▂▂ div [.] main
> 46.72% [div.c:42 -> div.c:39] 0 ± 24.1% ▃█▂▄▁▃▂▁ div [.] main
> 20.54% [random_r.c:357 -> random_r.c:394] 1 ± 33.5% ▅▂▁█▃▁▂▁ libc-2.27.so [.] __random_r
> 20.54% [random_r.c:357 -> random_r.c:380] 0 ± 39.4% ▁▁█▁██▅▁ libc-2.27.so [.] __random_r
> 20.54% [random_r.c:388 -> random_r.c:388] 0 libc-2.27.so [.] __random_r
> 20.54% [random_r.c:388 -> random_r.c:391] 0 ± 41.2% ▁▃▁▂█▄▃▁ libc-2.27.so [.] __random_r
> 17.04% [random.c:288 -> random.c:291] 0 ± 48.8% ▁▁▁▁███▁ libc-2.27.so [.] __random
> 17.04% [random.c:291 -> random.c:291] 0 ±100.0% ▁█▁▁▁▁▁▁ libc-2.27.so [.] __random
> 17.04% [random.c:293 -> random.c:293] 0 ±100.0% ▁█▁▁▁▁▁▁ libc-2.27.so [.] __random
> 17.04% [random.c:295 -> random.c:295] 0 ±100.0% ▁█▁▁▁▁▁▁ libc-2.27.so [.] __random
> 17.04% [random.c:295 -> random.c:295] 0 libc-2.27.so [.] __random
> 17.04% [random.c:298 -> random.c:298] 0 ± 75.6% ▃█▁▁▁▁▁▁ libc-2.27.so [.] __random
> 8.40% [div.c:22 -> div.c:25] 0 ± 42.1% ▁▃▁▁███▁ div [.] compute_flag
> 8.40% [div.c:27 -> div.c:28] 0 ± 41.8% ██▁▁▄▁▁▄ div [.] compute_flag
> 5.14% [rand.c:26 -> rand.c:27] 0 ± 37.8% ▁▁▁████▁ libc-2.27.so [.] rand
> 5.14% [rand.c:28 -> rand.c:28] 0 libc-2.27.so [.] rand
> 2.15% [rand@...+0 -> rand@...+0] 0 div [.] rand@plt
> 0.00% [kernel.kallsyms] [k] __x86_indirect_thunk_rax
> 0.00% [do_mmap+714 -> do_mmap+732] -10 [kernel.kallsyms] [k] do_mmap
> 0.00% [do_mmap+737 -> do_mmap+765] 1 [kernel.kallsyms] [k] do_mmap
> 0.00% [do_mmap+262 -> do_mmap+299] 0 [kernel.kallsyms] [k] do_mmap
> 0.00% [__x86_indirect_thunk_r15+0 -> __x86_indirect_thunk_r15+0] 7 [kernel.kallsyms] [k] __x86_indirect_thunk_r15
> 0.00% [native_sched_clock+0 -> native_sched_clock+119] -1 ± 38.5% ▄█▁ [kernel.kallsyms] [k] native_sched_clock
> 0.00% [native_write_msr+0 -> native_write_msr+16] -13 ± 47.1% ▁█▇▃▁▁ [kernel.kallsyms] [k] native_write_msr
>
> v7:
> ---
> 1. v6 got Jiri's ACK.
> 2. Rebase to latest perf/core branch.
>
> v6:
> ---
> 1. Jiri provides better code for using data__hpp_register() in ui_init().
> Use this code in v6.
>
> v5:
> ---
> 1. Refine the use of data__hpp_register() in ui_init() according to
> Jiri's suggestion.
>
> v4:
> ---
> 1. Rename the new option from '--noisy' to '--cycles-hist'
> 2. Remove the option '-n'.
> 3. Only update the spark value and stats when '--cycles-hist' is enabled.
> 4. Remove the code of printing '..'.
>
> v3:
> ---
> 1. Move the histogram to a separate column
> 2. Move the svals[] out of struct stats
>
> v2:
> ---
> Jiri got a compile error,
>
> CC builtin-diff.o
> builtin-diff.c: In function ‘compute_cycles_diff’:
> builtin-diff.c:712:10: error: taking the absolute value of unsigned type ‘u64’ {aka ‘long unsigned int’} has no effect [-Werror=absolute-value]
> 712 | labs(pair->block_info->cycles_spark[i] -
> | ^~~~
>
> Because the result of u64 - u64 is still u64. Now we change the type of
> cycles_spark[] to s64.
>
> Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
> ---
> tools/perf/Documentation/perf-diff.txt | 5 +
> tools/perf/builtin-diff.c | 143 +++++++++++++++++++++++++
> tools/perf/util/Build | 1 +
> tools/perf/util/annotate.c | 4 +
> tools/perf/util/annotate.h | 2 +
> tools/perf/util/sort.h | 4 +
> tools/perf/util/spark.c | 34 ++++++
> tools/perf/util/spark.h | 8 ++
> tools/perf/util/symbol.h | 2 +
> 9 files changed, 203 insertions(+)
> create mode 100644 tools/perf/util/spark.c
> create mode 100644 tools/perf/util/spark.h
>
> diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
> index d5cc15e651cf..f50ca0fef0a4 100644
> --- a/tools/perf/Documentation/perf-diff.txt
> +++ b/tools/perf/Documentation/perf-diff.txt
> @@ -95,6 +95,11 @@ OPTIONS
> diff.compute config option. See COMPARISON METHODS section for
> more info.
>
> +--cycles-hist::
> + Report a histogram and the standard deviation for cycles data.
> + It can help us to judge if the reported cycles data is noisy or
> + not. This option should be used with '-c cycles'.
> +
> -p::
> --period::
> Show period values for both compared hist entries.
> diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
> index 827e4800d862..45abef0314a8 100644
> --- a/tools/perf/builtin-diff.c
> +++ b/tools/perf/builtin-diff.c
> @@ -23,6 +23,7 @@
> #include "util/time-utils.h"
> #include "util/annotate.h"
> #include "util/map.h"
> +#include "util/spark.h"
> #include <linux/zalloc.h>
> #include <subcmd/pager.h>
> #include <subcmd/parse-options.h>
> @@ -52,6 +53,7 @@ enum {
> PERF_HPP_DIFF__FORMULA,
> PERF_HPP_DIFF__DELTA_ABS,
> PERF_HPP_DIFF__CYCLES,
> + PERF_HPP_DIFF__CYCLES_HIST,
>
> PERF_HPP_DIFF__MAX_INDEX
> };
> @@ -86,6 +88,7 @@ static bool force;
> static bool show_period;
> static bool show_formula;
> static bool show_baseline_only;
> +static bool cycles_hist;
> static unsigned int sort_compute = 1;
>
> static s64 compute_wdiff_w1;
> @@ -163,6 +166,10 @@ static struct header_column {
> [PERF_HPP_DIFF__CYCLES] = {
> .name = "[Program Block Range] Cycles Diff",
> .width = 70,
> + },
> + [PERF_HPP_DIFF__CYCLES_HIST] = {
> + .name = "stddev/Hist",
> + .width = NUM_SPARKS + 9,
> }
> };
>
> @@ -609,6 +616,9 @@ static void init_block_info(struct block_info *bi, struct symbol *sym,
> bi->cycles_aggr = ch->cycles_aggr;
> bi->num = ch->num;
> bi->num_aggr = ch->num_aggr;
> +
> + memcpy(bi->cycles_spark, ch->cycles_spark,
> + NUM_SPARKS * sizeof(u64));
> }
>
> static int process_block_per_sym(struct hist_entry *he)
> @@ -688,6 +698,21 @@ static struct hist_entry *get_block_pair(struct hist_entry *he,
> return NULL;
> }
>
> +static void init_spark_values(unsigned long *svals, int num)
> +{
> + for (int i = 0; i < num; i++)
> + svals[i] = 0;
> +}
> +
> +static void update_spark_value(unsigned long *svals, int num,
> + struct stats *stats, u64 val)
> +{
> + int n = stats->n;
> +
> + if (n < num)
> + svals[n] = val;
> +}
> +
> static void compute_cycles_diff(struct hist_entry *he,
> struct hist_entry *pair)
> {
> @@ -696,6 +721,26 @@ static void compute_cycles_diff(struct hist_entry *he,
> pair->diff.cycles =
> pair->block_info->cycles_aggr / pair->block_info->num_aggr -
> he->block_info->cycles_aggr / he->block_info->num_aggr;
> +
> + if (!cycles_hist)
> + return;
> +
> + init_stats(&pair->diff.stats);
> + init_spark_values(pair->diff.svals, NUM_SPARKS);
> +
> + for (int i = 0; i < pair->block_info->num; i++) {
> + u64 val;
> +
> + if (i >= he->block_info->num || i >= NUM_SPARKS)
> + break;
> +
> + val = labs(pair->block_info->cycles_spark[i] -
> + he->block_info->cycles_spark[i]);
> +
> + update_spark_value(pair->diff.svals, NUM_SPARKS,
> + &pair->diff.stats, val);
> + update_stats(&pair->diff.stats, val);
> + }
> }
> }
>
> @@ -1254,6 +1299,9 @@ static const struct option options[] = {
> "Show period values."),
> OPT_BOOLEAN('F', "formula", &show_formula,
> "Show formula."),
> + OPT_BOOLEAN(0, "cycles-hist", &cycles_hist,
> + "Show cycles histogram and standard deviation "
> + "- WARNING: use only with -c cycles."),
> OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
> "dump raw trace in ASCII"),
> OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
> @@ -1461,6 +1509,90 @@ static int hpp__color_cycles(struct perf_hpp_fmt *fmt,
> return __hpp__color_compare(fmt, hpp, he, COMPUTE_CYCLES);
> }
>
> +static int all_zero(unsigned long *vals, int len)
> +{
> + int i;
> +
> + for (i = 0; i < len; i++)
> + if (vals[i] != 0)
> + return 0;
> + return 1;
> +}
> +
> +static int print_cycles_spark(char *bf, int size, unsigned long *svals, u64 n)
> +{
> + int printed;
> +
> + if (n <= 1)
> + return 0;
> +
> + if (n > NUM_SPARKS)
> + n = NUM_SPARKS;
> + if (all_zero(svals, n))
> + return 0;
> +
> + printed = print_spark(bf, size, svals, n);
> + printed += scnprintf(bf + printed, size - printed, " ");
> + return printed;
> +}
> +
> +static int hpp__color_cycles_hist(struct perf_hpp_fmt *fmt,
> + struct perf_hpp *hpp, struct hist_entry *he)
> +{
> + struct diff_hpp_fmt *dfmt =
> + container_of(fmt, struct diff_hpp_fmt, fmt);
> + struct hist_entry *pair = get_pair_fmt(he, dfmt);
> + struct block_hist *bh = container_of(he, struct block_hist, he);
> + struct block_hist *bh_pair;
> + struct hist_entry *block_he;
> + char spark[32], buf[128];
> + double r;
> + int ret, pad;
> +
> + if (!pair) {
> + if (bh->block_idx)
> + hpp->skip = true;
> +
> + goto no_print;
> + }
> +
> + bh_pair = container_of(pair, struct block_hist, he);
> +
> + block_he = hists__get_entry(&bh_pair->block_hists, bh->block_idx);
> + if (!block_he) {
> + hpp->skip = true;
> + goto no_print;
> + }
> +
> + ret = print_cycles_spark(spark, sizeof(spark), block_he->diff.svals,
> + block_he->diff.stats.n);
> +
> + r = rel_stddev_stats(stddev_stats(&block_he->diff.stats),
> + avg_stats(&block_he->diff.stats));
> +
> + if (ret) {
> + /*
> + * Padding spaces if number of sparks less than NUM_SPARKS
> + * otherwise the output is not aligned.
> + */
> + pad = NUM_SPARKS - ((ret - 1) / 3);
> + scnprintf(buf, sizeof(buf), "%s%5.1f%% %s", "\u00B1", r, spark);
> + ret = scnprintf(hpp->buf, hpp->size, "%*s",
> + dfmt->header_width, buf);
> +
> + if (pad) {
> + ret += scnprintf(hpp->buf + ret, hpp->size - ret,
> + "%-*s", pad, " ");
> + }
> +
> + return ret;
> + }
> +
> +no_print:
> + return scnprintf(hpp->buf, hpp->size, "%*s",
> + dfmt->header_width, " ");
> +}
> +
> static void
> hpp__entry_unpair(struct hist_entry *he, int idx, char *buf, size_t size)
> {
> @@ -1666,6 +1798,10 @@ static void data__hpp_register(struct data__file *d, int idx)
> fmt->color = hpp__color_cycles;
> fmt->sort = hist_entry__cmp_nop;
> break;
> + case PERF_HPP_DIFF__CYCLES_HIST:
> + fmt->color = hpp__color_cycles_hist;
> + fmt->sort = hist_entry__cmp_nop;
> + break;
> default:
> fmt->sort = hist_entry__cmp_nop;
> break;
> @@ -1691,10 +1827,14 @@ static int ui_init(void)
> * PERF_HPP_DIFF__DELTA
> * PERF_HPP_DIFF__RATIO
> * PERF_HPP_DIFF__WEIGHTED_DIFF
> + * PERF_HPP_DIFF__CYCLES
> */
> data__hpp_register(d, i ? compute_2_hpp[compute] :
> PERF_HPP_DIFF__BASELINE);
>
> + if (cycles_hist && i)
> + data__hpp_register(d, PERF_HPP_DIFF__CYCLES_HIST);
> +
> /*
> * And the rest:
> *
> @@ -1849,6 +1989,9 @@ int cmd_diff(int argc, const char **argv)
> if (quiet)
> perf_quiet_option();
>
> + if (cycles_hist && (compute != COMPUTE_CYCLES))
> + usage_with_options(diff_usage, options);
> +
> symbol__annotation_init();
>
> if (symbol__init(NULL) < 0)
> diff --git a/tools/perf/util/Build b/tools/perf/util/Build
> index 0b4d8e0d474c..9fa215dc1476 100644
> --- a/tools/perf/util/Build
> +++ b/tools/perf/util/Build
> @@ -92,6 +92,7 @@ perf-y += cloexec.o
> perf-y += call-path.o
> perf-y += rwsem.o
> perf-y += thread-stack.o
> +perf-y += spark.o
> perf-$(CONFIG_AUXTRACE) += auxtrace.o
> perf-$(CONFIG_AUXTRACE) += intel-pt-decoder/
> perf-$(CONFIG_AUXTRACE) += intel-pt.o
> diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> index 1748f528b6e9..9497a93c95f3 100644
> --- a/tools/perf/util/annotate.c
> +++ b/tools/perf/util/annotate.c
> @@ -852,6 +852,10 @@ static int __symbol__account_cycles(struct cyc_hist *ch,
> ch[offset].start < start)
> return 0;
> }
> +
> + if (ch[offset].num < NUM_SPARKS)
> + ch[offset].cycles_spark[ch[offset].num] = cycles;
> +
> ch[offset].have_start = have_start;
> ch[offset].start = start;
> ch[offset].cycles += cycles;
> diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
> index d94be9140e31..7776ff4480af 100644
> --- a/tools/perf/util/annotate.h
> +++ b/tools/perf/util/annotate.h
> @@ -11,6 +11,7 @@
> #include <pthread.h>
> #include <asm/bug.h>
> #include "symbol_conf.h"
> +#include "spark.h"
>
> struct hist_browser_timer;
> struct hist_entry;
> @@ -235,6 +236,7 @@ struct cyc_hist {
> u64 cycles_aggr;
> u64 cycles_max;
> u64 cycles_min;
> + s64 cycles_spark[NUM_SPARKS];
> u32 num;
> u32 num_aggr;
> u8 have_start;
> diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h
> index 7b93f34ac1f4..5aff9542d9b7 100644
> --- a/tools/perf/util/sort.h
> +++ b/tools/perf/util/sort.h
> @@ -10,6 +10,8 @@
> #include "callchain.h"
> #include "values.h"
> #include "hist.h"
> +#include "stat.h"
> +#include "spark.h"
>
> struct option;
> struct thread;
> @@ -71,6 +73,8 @@ struct hist_entry_diff {
> /* PERF_HPP_DIFF__CYCLES */
> s64 cycles;
> };
> + struct stats stats;
> + unsigned long svals[NUM_SPARKS];
> };
>
> struct hist_entry_ops {
> diff --git a/tools/perf/util/spark.c b/tools/perf/util/spark.c
> new file mode 100644
> index 000000000000..70272a8b81a6
> --- /dev/null
> +++ b/tools/perf/util/spark.c
> @@ -0,0 +1,34 @@
> +#include <stdio.h>
> +#include <limits.h>
> +#include <string.h>
> +#include <stdlib.h>
> +#include "spark.h"
> +#include "stat.h"
> +
> +#define SPARK_SHIFT 8
> +
> +/* Print spark lines on outf for numval values in val. */
> +int print_spark(char *bf, int size, unsigned long *val, int numval)
> +{
> + static const char *ticks[NUM_SPARKS] = {
> + "▁", "▂", "▃", "▄", "▅", "▆", "▇", "█"
> + };
> + int i, printed = 0;
> + unsigned long min = ULONG_MAX, max = 0, f;
> +
> + for (i = 0; i < numval; i++) {
> + if (val[i] < min)
> + min = val[i];
> + if (val[i] > max)
> + max = val[i];
> + }
> + f = ((max - min) << SPARK_SHIFT) / (NUM_SPARKS - 1);
> + if (f < 1)
> + f = 1;
> + for (i = 0; i < numval; i++) {
> + printed += scnprintf(bf + printed, size - printed, "%s",
> + ticks[((val[i] - min) << SPARK_SHIFT) / f]);
> + }
> +
> + return printed;
> +}
> diff --git a/tools/perf/util/spark.h b/tools/perf/util/spark.h
> new file mode 100644
> index 000000000000..25402d7d7a64
> --- /dev/null
> +++ b/tools/perf/util/spark.h
> @@ -0,0 +1,8 @@
> +#ifndef SPARK_H
> +#define SPARK_H 1
> +
> +#define NUM_SPARKS 8
> +
> +int print_spark(char *bf, int size, unsigned long *val, int numval);
> +
> +#endif
> diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
> index 0b0c6b5b1899..cc2a89b99d3d 100644
> --- a/tools/perf/util/symbol.h
> +++ b/tools/perf/util/symbol.h
> @@ -11,6 +11,7 @@
> #include <stdio.h>
> #include "path.h"
> #include "symbol_conf.h"
> +#include "spark.h"
>
> #ifdef HAVE_LIBELF_SUPPORT
> #include <libelf.h>
> @@ -111,6 +112,7 @@ struct block_info {
> u64 end;
> u64 cycles;
> u64 cycles_aggr;
> + s64 cycles_spark[NUM_SPARKS];
> int num;
> int num_aggr;
> refcount_t refcnt;
>
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