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Message-ID: <50587EC4.7070804@gmail.com>
Date: Tue, 18 Sep 2012 08:01:40 -0600
From: David Ahern <dsahern@...il.com>
To: Dong Hao <haodong@...ux.vnet.ibm.com>
CC: acme@...radead.org, mtosatti@...hat.com, avi@...hat.com,
mingo@...nel.org, linux-kernel@...r.kernel.org,
kvm@...r.kernel.org, xiaoguangrong@...ux.vnet.ibm.com,
runzhen@...ux.vnet.ibm.com
Subject: Re: [PATCH v8 2/3] perf: move stat related code to util/stat.c
On 9/17/12 2:31 AM, Dong Hao wrote:
> From: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
>
> Then, the code can be shared between kvm events and perf stat
>
> [ Dong Hao <haodong@...ux.vnet.ibm.com>: rebase it on acme's git tree ]
> Signed-off-by: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
> Signed-off-by: Dong Hao <haodong@...ux.vnet.ibm.com>
> ---
> tools/perf/Makefile | 1 +
> tools/perf/builtin-stat.c | 56 +------------------------------------------
> tools/perf/util/stat.c | 57 +++++++++++++++++++++++++++++++++++++++++++++
> tools/perf/util/stat.h | 16 ++++++++++++
> 4 files changed, 76 insertions(+), 54 deletions(-)
> create mode 100644 tools/perf/util/stat.c
> create mode 100644 tools/perf/util/stat.h
>
> diff --git a/tools/perf/Makefile b/tools/perf/Makefile
> index 209774b..5077f8e 100644
> --- a/tools/perf/Makefile
> +++ b/tools/perf/Makefile
> @@ -406,6 +406,7 @@ LIB_OBJS += $(OUTPUT)util/target.o
> LIB_OBJS += $(OUTPUT)util/rblist.o
> LIB_OBJS += $(OUTPUT)util/intlist.o
> LIB_OBJS += $(OUTPUT)util/vdso.o
> +LIB_OBJS += $(OUTPUT)util/stat.o
>
> LIB_OBJS += $(OUTPUT)ui/helpline.o
> LIB_OBJS += $(OUTPUT)ui/hist.o
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index dab347d..3c43a35 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -51,13 +51,13 @@
> #include "util/evsel.h"
> #include "util/debug.h"
> #include "util/color.h"
> +#include "util/stat.h"
> #include "util/header.h"
> #include "util/cpumap.h"
> #include "util/thread.h"
> #include "util/thread_map.h"
>
> #include <sys/prctl.h>
> -#include <math.h>
> #include <locale.h>
>
> #define DEFAULT_SEPARATOR " "
> @@ -199,11 +199,6 @@ static int output_fd;
>
> static volatile int done = 0;
>
> -struct stats
> -{
> - double n, mean, M2;
> -};
> -
> struct perf_stat {
> struct stats res_stats[3];
> };
> @@ -220,50 +215,6 @@ static void perf_evsel__free_stat_priv(struct perf_evsel *evsel)
> evsel->priv = NULL;
> }
>
> -static void update_stats(struct stats *stats, u64 val)
> -{
> - double delta;
> -
> - stats->n++;
> - delta = val - stats->mean;
> - stats->mean += delta / stats->n;
> - stats->M2 += delta*(val - stats->mean);
> -}
> -
> -static double avg_stats(struct stats *stats)
> -{
> - return stats->mean;
> -}
> -
> -/*
> - * http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
> - *
> - * (\Sum n_i^2) - ((\Sum n_i)^2)/n
> - * s^2 = -------------------------------
> - * n - 1
> - *
> - * http://en.wikipedia.org/wiki/Stddev
> - *
> - * The std dev of the mean is related to the std dev by:
> - *
> - * s
> - * s_mean = -------
> - * sqrt(n)
> - *
> - */
> -static double stddev_stats(struct stats *stats)
> -{
> - double variance, variance_mean;
> -
> - if (!stats->n)
> - return 0.0;
> -
> - variance = stats->M2 / (stats->n - 1);
> - variance_mean = variance / stats->n;
> -
> - return sqrt(variance_mean);
> -}
> -
> static struct stats runtime_nsecs_stats[MAX_NR_CPUS];
> static struct stats runtime_cycles_stats[MAX_NR_CPUS];
> static struct stats runtime_stalled_cycles_front_stats[MAX_NR_CPUS];
> @@ -559,10 +510,7 @@ static int run_perf_stat(int argc __maybe_unused, const char **argv)
>
> static void print_noise_pct(double total, double avg)
> {
> - double pct = 0.0;
> -
> - if (avg)
> - pct = 100.0*total/avg;
> + double pct = rel_stddev_stats(total, avg);
>
> if (csv_output)
> fprintf(output, "%s%.2f%%", csv_sep, pct);
> diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
> new file mode 100644
> index 0000000..2374212
> --- /dev/null
> +++ b/tools/perf/util/stat.c
> @@ -0,0 +1,57 @@
> +#include <math.h>
> +
> +#include "stat.h"
> +
> +void update_stats(struct stats *stats, u64 val)
> +{
> + double delta;
> +
> + stats->n++;
> + delta = val - stats->mean;
> + stats->mean += delta / stats->n;
> + stats->M2 += delta*(val - stats->mean);
> +}
> +
> +double avg_stats(struct stats *stats)
> +{
> + return stats->mean;
> +}
> +
> +/*
> + * http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
> + *
> + * (\Sum n_i^2) - ((\Sum n_i)^2)/n
> + * s^2 = -------------------------------
> + * n - 1
> + *
> + * http://en.wikipedia.org/wiki/Stddev
> + *
> + * The std dev of the mean is related to the std dev by:
> + *
> + * s
> + * s_mean = -------
> + * sqrt(n)
> + *
> + */
> +double stddev_stats(struct stats *stats)
> +{
> + double variance, variance_mean;
> +
> + if (!stats->n)
> + return 0.0;
> +
> + variance = stats->M2 / (stats->n - 1);
> + variance_mean = variance / stats->n;
> +
> + return sqrt(variance_mean);
> +}
> +
> +double rel_stddev_stats(double stddev, double avg)
> +{
> + double pct = 0.0;
> +
> + if (avg)
> + pct = 100.0 * stddev/avg;
> +
> + return pct;
> +}
rel_stddev_stats should take the struct stats as an input and use
elements from it to compute the return value. perf-stat's relative
stddev sites can be fixed later.
> diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
> new file mode 100644
> index 0000000..588367c
> --- /dev/null
> +++ b/tools/perf/util/stat.h
> @@ -0,0 +1,16 @@
> +#ifndef __PERF_STATS_H
> +#define __PERF_STATS_H
> +
> +#include "types.h"
> +
> +struct stats
> +{
> + double n, mean, M2;
> +};
> +
> +void update_stats(struct stats *stats, u64 val);
> +double avg_stats(struct stats *stats);
> +double stddev_stats(struct stats *stats);
> +double rel_stddev_stats(double stddev, double avg);
> +
> +#endif
>
--
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