Re: [dpdk-dev] [PATCH v3 3/3] test: add tests for reciprocal based division

[Pavan Nikhilesh Bhagavatula <pbhagavatula@caviumnetworks.com>]

On Mon, Sep 04, 2017 at 09:18:37AM +0000, Burakov, Anatoly wrote:

Hi Burakov,

> Hi Pavan,
>
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Pavan Nikhilesh
> > Sent: Sunday, September 3, 2017 1:36 PM
> > To: dev@dpdk.org
> > Cc: Dumitrescu, Cristian <cristian.dumitrescu@intel.com>;
> > stephen@networkplumber.org; Pavan Nikhilesh
> > <pbhagavatula@caviumnetworks.com>
> > Subject: [dpdk-dev] [PATCH v3 3/3] test: add tests for reciprocal based
> > division
> >
> > This commit provides a set of tests for verifying the correctness and
> > performance of both unsigned 32 and 64bit reciprocal based division.
> >
> > Signed-off-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>
> > ---
> >  test/test/Makefile                        |   2 +
> >  test/test/test_reciprocal_division.c      | 109 ++++++++++++++++++
> >  test/test/test_reciprocal_division_perf.c | 181
> > ++++++++++++++++++++++++++++++
> >  3 files changed, 292 insertions(+)
> >  create mode 100644 test/test/test_reciprocal_division.c
> >  create mode 100644 test/test/test_reciprocal_division_perf.c
> >
> > diff --git a/test/test/Makefile b/test/test/Makefile index 42d9a49..6017862
> > 100644
> > --- a/test/test/Makefile
> > +++ b/test/test/Makefile
> > @@ -94,6 +94,8 @@ SRCS-y += test_cycles.c  SRCS-y += test_spinlock.c
> > SRCS-y += test_memory.c  SRCS-y += test_memzone.c
> > +SRCS-y += test_reciprocal_division.c
> > +SRCS-y += test_reciprocal_division_perf.c
> >
> >  SRCS-y += test_ring.c
> >  SRCS-y += test_ring_perf.c
> > diff --git a/test/test/test_reciprocal_division.c
> > b/test/test/test_reciprocal_division.c
> > new file mode 100644
> > index 0000000..771ea64
> > --- /dev/null
> > +++ b/test/test/test_reciprocal_division.c
> > @@ -0,0 +1,109 @@
> > +/*
> > + *   BSD LICENSE
> > + *
> > + *   Copyright (C) Cavium, Inc. 2017.
> > + *
> > + *   Redistribution and use in source and binary forms, with or without
> > + *   modification, are permitted provided that the following conditions
> > + *   are met:
> > + *
> > + *     * Redistributions of source code must retain the above copyright
> > + *       notice, this list of conditions and the following disclaimer.
> > + *     * Redistributions in binary form must reproduce the above copyright
> > + *       notice, this list of conditions and the following disclaimer in
> > + *       the documentation and/or other materials provided with the
> > + *       distribution.
> > + *     * Neither the name of Cavium, Inc nor the names of its
> > + *       contributors may be used to endorse or promote products derived
> > + *       from this software without specific prior written permission.
> > + *
> > + *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
> > CONTRIBUTORS
> > + *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
> > NOT
> > + *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
> > FITNESS FOR
> > + *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
> > COPYRIGHT
> > + *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
> > INCIDENTAL,
> > + *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
> > NOT
> > + *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
> > OF USE,
> > + *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
> > AND ON ANY
> > + *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
> > TORT
> > + *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
> > THE USE
> > + *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
> > DAMAGE.
> > + */
> > +
> > +#include "test.h"
> > +
> > +#include <stdio.h>
> > +#include <unistd.h>
> > +#include <inttypes.h>
> > +
> > +#include <rte_common.h>
> > +#include <rte_cycles.h>
> > +#include <rte_random.h>
> > +#include <rte_reciprocal.h>
> > +
> > +#define MAX_ITERATIONS	1000000
> > +#define DIVIDE_ITER		100
> > +
> > +static int
> > +test_reciprocal_division(void)
> > +{
> > +	int i;
> > +	int result = 0;
> > +	uint32_t divisor_u32 = 0;
> > +	uint32_t dividend_u32;
> > +	uint32_t nresult_u32;
> > +	uint32_t rresult_u32;
> > +	uint64_t divisor_u64 = 0;
> > +	uint64_t dividend_u64;
> > +	uint64_t nresult_u64;
> > +	uint64_t rresult_u64;
> > +	struct rte_reciprocal_u32 reci_u32;
> > +	struct rte_reciprocal_u64 reci_u64;
> > +
> > +	rte_srand(rte_rdtsc());
> > +	printf("Validating unsigned 32bit division.\n");
> > +	for (i = 0; i < MAX_ITERATIONS; i++) {
> > +		/* Change divisor every DIVIDE_ITER iterations. */
> > +		if (i % DIVIDE_ITER == 0) {
> > +			divisor_u32 = rte_rand();
> > +			reci_u32 = rte_reciprocal_value_u32(divisor_u32);
> > +		}
> > +
> > +		dividend_u32 = rte_rand();
> > +		nresult_u32 = dividend_u32 / divisor_u32;
> > +		rresult_u32 = rte_reciprocal_divide_u32(dividend_u32,
> > +				&reci_u32);
> > +		if (nresult_u32 != rresult_u32) {
> > +			printf("Division failed, expected %"PRIu32" "
> > +				   "result %"PRIu32"",
> > +					nresult_u32, rresult_u32);
> > +			result = 1;
> > +			break;
> > +		}
> > +	}
> > +
> > +	printf("Validating unsigned 64bit division.\n");
> > +	for (i = 0; i < MAX_ITERATIONS; i++) {
> > +		/* Change divisor every DIVIDE_ITER iterations. */
> > +		if (i % DIVIDE_ITER == 0) {
> > +			divisor_u64 = rte_rand();
> > +			reci_u64 = rte_reciprocal_value_u64(divisor_u64);
> > +		}
> > +
> > +		dividend_u64 = rte_rand();
> > +		nresult_u64 = dividend_u64 / divisor_u64;
> > +		rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
> > +				&reci_u64);
> > +		if (nresult_u64 != rresult_u64) {
> > +			printf("Division failed, expected %"PRIu64" "
> > +				   "result %"PRIu64"",
> > +					nresult_u64, rresult_u64);
> > +			result = 1;
> > +			break;
> > +		}
> > +	}
> > +
> > +	return result;
> > +}
> > +
> > +REGISTER_TEST_COMMAND(reciprocal_division, test_reciprocal_division);
> > diff --git a/test/test/test_reciprocal_division_perf.c
> > b/test/test/test_reciprocal_division_perf.c
> > new file mode 100644
> > index 0000000..31f069d
> > --- /dev/null
> > +++ b/test/test/test_reciprocal_division_perf.c
> > @@ -0,0 +1,181 @@
> > +/*
> > + *   BSD LICENSE
> > + *
> > + *   Copyright (C) Cavium, Inc. 2017.
> > + *
> > + *   Redistribution and use in source and binary forms, with or without
> > + *   modification, are permitted provided that the following conditions
> > + *   are met:
> > + *
> > + *     * Redistributions of source code must retain the above copyright
> > + *       notice, this list of conditions and the following disclaimer.
> > + *     * Redistributions in binary form must reproduce the above copyright
> > + *       notice, this list of conditions and the following disclaimer in
> > + *       the documentation and/or other materials provided with the
> > + *       distribution.
> > + *     * Neither the name of Cavium, Inc nor the names of its
> > + *       contributors may be used to endorse or promote products derived
> > + *       from this software without specific prior written permission.
> > + *
> > + *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
> > CONTRIBUTORS
> > + *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
> > NOT
> > + *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
> > FITNESS FOR
> > + *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
> > COPYRIGHT
> > + *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
> > INCIDENTAL,
> > + *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
> > NOT
> > + *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
> > OF USE,
> > + *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
> > AND ON ANY
> > + *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
> > TORT
> > + *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
> > THE USE
> > + *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
> > DAMAGE.
> > + */
> > +
> > +#include "test.h"
> > +
> > +#include <stdio.h>
> > +#include <unistd.h>
> > +#include <inttypes.h>
> > +
> > +#include <rte_common.h>
> > +#include <rte_cycles.h>
> > +#include <rte_random.h>
> > +#include <rte_reciprocal.h>
> > +
> > +#define MAX_ITERATIONS	1000000
> > +#define DIVIDE_ITER		100
> > +
> > +static int
> > +test_reciprocal_division_perf(void)
> > +{
> > +	int result = 0;
> > +	uint32_t divisor_u32 = 0;
> > +	uint32_t dividend_u32;
> > +	uint32_t nresult_u32;
> > +	uint32_t rresult_u32;
> > +	uint64_t divisor_u64 = 0;
> > +	uint64_t dividend_u64;
> > +	uint64_t nresult_u64;
> > +	uint64_t rresult_u64;
> > +	uint64_t cur_cyc;
> > +	uint64_t tot_cyc_n = 0;
> > +	uint64_t tot_cyc_r = 0;
> > +	uint64_t i;
> > +	struct rte_reciprocal_u32 reci_u32 = {0};
> > +	struct rte_reciprocal_u64 reci_u64 = {0};
> > +
> > +	rte_srand(rte_rdtsc());
> > +	printf("Validating unsigned 32bit division.\n");
> > +	for (i = 0; i < MAX_ITERATIONS; i++) {
> > +		/* Change divisor every DIVIDE_ITER iterations. */
> > +		if (i % DIVIDE_ITER == 0) {
> > +			divisor_u32 = rte_rand();
> > +			reci_u32 = rte_reciprocal_value_u32(divisor_u32);
> > +		}
> > +
> > +		dividend_u32 = rte_rand();
> > +		cur_cyc = rte_rdtsc();
> > +		nresult_u32 = dividend_u32 / divisor_u32;
> > +		tot_cyc_n += rte_rdtsc() - cur_cyc;
> > +
> > +		cur_cyc = rte_rdtsc();
>
> Is there any particular reason for calling rte_rdtsc() twice in a row? Instead of, say, doing something like this:
>
> start = rdtsc();
> // do something
> split = rdtsc();
> // do something else
> end = rdtsc();
> // figure out which cycle value goes where
>

No particular reason for doing so. I will do the changes in v4.

tot_cyc_n += split - start;
tot_cyc_r += end - split;

Thanks for the inputs.
-Pavan.

> > +		rresult_u32 = rte_reciprocal_divide_u32(dividend_u32,
> > +				&reci_u32);
> > +		tot_cyc_r += rte_rdtsc() - cur_cyc;
> > +		if (nresult_u32 != rresult_u32) {
> > +			printf("Division failed, expected %"PRIu32" "
> > +					"result %"PRIu32"",
> > +					nresult_u32, rresult_u32);
> > +			result = 1;
> > +			break;
> > +		}
> > +	}
> > +	printf("32bit Division results:\n");
> > +	printf("Total number of cycles normal division     : %"PRIu64"\n",
> > +			tot_cyc_n);
> > +	printf("Total number of cycles reciprocal division : %"PRIu64"\n",
> > +			tot_cyc_r);
> > +	printf("Cycles per division(normal) : %3.2f\n",
> > +			((double)tot_cyc_n)/i);
> > +	printf("Cycles per division(normal) : %3.2f\n\n",
> > +			((double)tot_cyc_r)/i);
> > +
> > +	tot_cyc_n = 0;
> > +	tot_cyc_r = 0;
> > +	printf("Validating unsigned 64bit division.\n");
> > +
> > +	for (i = 0; i < MAX_ITERATIONS; i++) {
> > +		/* Change divisor every DIVIDE_ITER iterations. */
> > +		if (i % DIVIDE_ITER == 0) {
> > +			divisor_u64 = rte_rand();
> > +			reci_u64 = rte_reciprocal_value_u64(divisor_u64);
> > +		}
> > +
> > +		dividend_u64 = rte_rand();
> > +		cur_cyc = rte_rdtsc();
> > +		nresult_u64 = dividend_u64 / divisor_u64;
> > +		tot_cyc_n += rte_rdtsc() - cur_cyc;
> > +
> > +		cur_cyc = rte_rdtsc();
>
> Same as above
>
> > +		rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
> > +				&reci_u64);
> > +		tot_cyc_r += rte_rdtsc() - cur_cyc;
> > +		if (nresult_u64 != rresult_u64) {
> > +			printf("Division failed, expected %"PRIu64" "
> > +					"result %"PRIu64"",
> > +					nresult_u64, rresult_u64);
> > +			result = 1;
> > +			break;
> > +		}
> > +	}
> > +	printf("64bit Division results:\n");
> > +	printf("Total number of cycles normal division     : %"PRIu64"\n",
> > +			tot_cyc_n);
> > +	printf("Total number of cycles reciprocal division : %"PRIu64"\n",
> > +			tot_cyc_r);
> > +	printf("Cycles per division(normal) : %3.2f\n",
> > +			((double)tot_cyc_n)/i);
> > +	printf("Cycles per division(normal) : %3.2f\n\n",
> > +			((double)tot_cyc_r)/i);
> > +
> > +	printf("Validating unsigned 64bit division with 32bit divisor.\n");
> > +	for (i = 0; i < MAX_ITERATIONS; i++) {
> > +		/* Change divisor every DIVIDE_ITER iterations. */
> > +		if (i % DIVIDE_ITER == 0) {
> > +			divisor_u64 = rte_rand() >> 32;
> > +			reci_u64 = rte_reciprocal_value_u64(divisor_u64);
> > +		}
> > +
> > +		dividend_u64 = rte_rand();
> > +		cur_cyc = rte_rdtsc();
> > +		nresult_u64 = dividend_u64 / divisor_u64;
> > +		tot_cyc_n += rte_rdtsc() - cur_cyc;
> > +
> > +		cur_cyc = rte_rdtsc();
> > +		rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
> > +				&reci_u64);
> > +		tot_cyc_r += rte_rdtsc() - cur_cyc;
> > +		if (nresult_u64 != rresult_u64) {
> > +			printf("Division failed, expected %"PRIu64" "
> > +					"result %"PRIu64"",
> > +					nresult_u64, rresult_u64);
> > +			result = 1;
> > +			break;
> > +		}
> > +	}
> > +	printf("64bit Division results:\n");
> > +	printf("Total number of cycles normal division     : %"PRIu64"\n",
> > +			tot_cyc_n);
> > +	printf("Total number of cycles reciprocal division : %"PRIu64"\n",
> > +			tot_cyc_r);
> > +	printf("Cycles per division(normal) : %3.2f\n",
> > +			((double)tot_cyc_n)/i);
> > +	printf("Cycles per division(normal) : %3.2f\n",
> > +			((double)tot_cyc_r)/i);
> > +
> > +	tot_cyc_n = 0;
> > +	tot_cyc_r = 0;
> > +
> > +	return result;
> > +}
> > +
> > +REGISTER_TEST_COMMAND(reciprocal_division_perf,
> > +test_reciprocal_division_perf);
> > --
> > 2.7.4
>