Hi Mattias,
Please see few comments below.
On Fri, Jul 08, 2022 at 02:56:07PM +0200, Mattias Rönnblom wrote:
> Add performance test for the rte_raw_cksum() function, which delegates
> the actual work to __rte_raw_cksum(), which in turn is used by other
> functions in need of Internet checksum calculation.
>
> Signed-off-by: Mattias Rönnblom <mattias.ronnb...@ericsson.com>
>
> ---
>
> v2:
> * Added __rte_unused to unused volatile variable, to keep the Intel
> compiler happy.
> ---
> MAINTAINERS | 1 +
> app/test/meson.build | 1 +
> app/test/test_cksum_perf.c | 118 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 120 insertions(+)
> create mode 100644 app/test/test_cksum_perf.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c923712946..2a4c99e05a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1414,6 +1414,7 @@ Network headers
> M: Olivier Matz <olivier.m...@6wind.com>
> F: lib/net/
> F: app/test/test_cksum.c
> +F: app/test/test_cksum_perf.c
>
> Packet CRC
> M: Jasvinder Singh <jasvinder.si...@intel.com>
> diff --git a/app/test/meson.build b/app/test/meson.build
> index 431c5bd318..191db03d1d 100644
> --- a/app/test/meson.build
> +++ b/app/test/meson.build
> @@ -18,6 +18,7 @@ test_sources = files(
> 'test_bpf.c',
> 'test_byteorder.c',
> 'test_cksum.c',
> + 'test_cksum_perf.c',
> 'test_cmdline.c',
> 'test_cmdline_cirbuf.c',
> 'test_cmdline_etheraddr.c',
> diff --git a/app/test/test_cksum_perf.c b/app/test/test_cksum_perf.c
> new file mode 100644
> index 0000000000..bff73cb3bb
> --- /dev/null
> +++ b/app/test/test_cksum_perf.c
> @@ -0,0 +1,118 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2022 Ericsson AB
> + */
> +
> +#include <stdio.h>
> +
> +#include <rte_common.h>
> +#include <rte_cycles.h>
> +#include <rte_ip.h>
> +#include <rte_malloc.h>
> +#include <rte_random.h>
> +
> +#include "test.h"
> +
> +#define NUM_BLOCKS (10)
> +#define ITERATIONS (1000000)
Parenthesis can be safely removed
> +
> +static const size_t data_sizes[] = { 20, 21, 100, 101, 1500, 1501 };
> +
> +static __rte_noinline uint16_t
> +do_rte_raw_cksum(const void *buf, size_t len)
> +{
> + return rte_raw_cksum(buf, len);
> +}
I don't understand the need to have this wrapper, especially marked
__rte_noinline. What is the objective?
Note that when I remove the __rte_noinline, the performance is better
for size 20 and 21.
> +
> +static void
> +init_block(void *buf, size_t len)
Can buf be a (char *) instead?
It would avoid a cast below.
> +{
> + size_t i;
> +
> + for (i = 0; i < len; i++)
> + ((char *)buf)[i] = (uint8_t)rte_rand();
> +}
> +
> +static int
> +test_cksum_perf_size_alignment(size_t block_size, bool aligned)
> +{
> + char *data[NUM_BLOCKS];
> + char *blocks[NUM_BLOCKS];
> + unsigned int i;
> + uint64_t start;
> + uint64_t end;
> + /* Floating point to handle low (pseudo-)TSC frequencies */
> + double block_latency;
> + double byte_latency;
> + volatile __rte_unused uint64_t sum = 0;
> +
> + for (i = 0; i < NUM_BLOCKS; i++) {
> + data[i] = rte_malloc(NULL, block_size + 1, 0);
> +
> + if (data[i] == NULL) {
> + printf("Failed to allocate memory for block\n");
> + return TEST_FAILED;
> + }
> +
> + init_block(data[i], block_size + 1);
> +
> + blocks[i] = aligned ? data[i] : data[i] + 1;
> + }
> +
> + start = rte_rdtsc();
> +
> + for (i = 0; i < ITERATIONS; i++) {
> + unsigned int j;
> + for (j = 0; j < NUM_BLOCKS; j++)
> + sum += do_rte_raw_cksum(blocks[j], block_size);
> + }
> +
> + end = rte_rdtsc();
> +
> + block_latency = (end - start) / (double)(ITERATIONS * NUM_BLOCKS);
> + byte_latency = block_latency / block_size;
> +
> + printf("%-9s %10zd %19.1f %16.2f\n", aligned ? "Aligned" : "Unaligned",
> + block_size, block_latency, byte_latency);
When I run the test on my dev machine, I get the following results,
which are quite reproductible:
Aligned 20 10.4 0.52 (range is 0.48 - 0.52)
Unaligned 20 7.9 0.39 (range is 0.39 - 0.40)
...
If I increase the number of iterations, the first results
change significantly:
Aligned 20 8.2 0.42 (range is 0.41 - 0.42)
Unaligned 20 8.0 0.40 (always this value)
To have more precise tests with small size, would it make sense to
target a test time instead of an iteration count? Something like
this:
#define ITERATIONS 1000000
uint64_t iterations = 0;
...
do {
for (i = 0; i < ITERATIONS; i++) {
unsigned int j;
for (j = 0; j < NUM_BLOCKS; j++)
sum += do_rte_raw_cksum(blocks[j], block_size);
}
iterations += ITERATIONS;
end = rte_rdtsc();
} while ((end - start) < rte_get_tsc_hz());
block_latency = (end - start) / (double)(iterations * NUM_BLOCKS);
After this change, the aligned and unaligned cases have the same
performance on my machine.
> +
> + for (i = 0; i < NUM_BLOCKS; i++)
> + rte_free(data[i]);
> +
> + return TEST_SUCCESS;
> +}
> +
> +static int
> +test_cksum_perf_size(size_t block_size)
> +{
> + int rc;
> +
> + rc = test_cksum_perf_size_alignment(block_size, true);
> + if (rc != TEST_SUCCESS)
> + return rc;
> +
> + rc = test_cksum_perf_size_alignment(block_size, false);
> +
> + return rc;
> +}
> +
> +static int
> +test_cksum_perf(void)
> +{
> + uint16_t i;
> +
> + printf("### rte_raw_cksum() performance ###\n");
> + printf("Alignment Block size TSC cycles/block TSC cycles/byte\n");
> +
> + for (i = 0; i < RTE_DIM(data_sizes); i++) {
> + int rc;
> +
> + rc = test_cksum_perf_size(data_sizes[i]);
> + if (rc != TEST_SUCCESS)
> + return rc;
> + }
> +
> + return TEST_SUCCESS;
> +}
> +
> +
> +REGISTER_TEST_COMMAND(cksum_perf_autotest, test_cksum_perf);
> +
The last empty line can be removed.
> --
> 2.25.1
>
