From 27c2e74719614df32e5358b9adfbed013ac7991c Mon Sep 17 00:00:00 2001 From: Pablo de Lara Date: Wed, 13 Dec 2017 13:14:08 +0000 Subject: [PATCH] app/crypto-perf: support IMIX Add support for IMIX performance tests, where a distribution of various packet sizes can be submitted to a crypto device, testing a closer to a real world scenario. A sequence of packet sizes, selected randomly from a list of packet sizes (with "buffer-sz" parameter) with a list of the weights per packet size (using "imix" parameter), is generated (the length of this sequence is the same length as the pool, set with "pool-sz" parameter). This sequence is used repeteadly for all the crypto operations submitted to the crypto device (with "--total-ops" parameter). Signed-off-by: Pablo de Lara Acked-by: Fan Zhang --- app/test-crypto-perf/cperf_ops.c | 77 +++++++++++----- app/test-crypto-perf/cperf_ops.h | 2 +- app/test-crypto-perf/cperf_options.h | 4 + app/test-crypto-perf/cperf_options_parsing.c | 61 +++++++++++-- app/test-crypto-perf/cperf_test_latency.c | 4 +- .../cperf_test_pmd_cyclecount.c | 8 +- app/test-crypto-perf/cperf_test_throughput.c | 3 +- app/test-crypto-perf/cperf_test_verify.c | 3 +- app/test-crypto-perf/main.c | 89 ++++++++++++++++--- doc/guides/tools/cryptoperf.rst | 14 +++ 10 files changed, 220 insertions(+), 45 deletions(-) diff --git a/app/test-crypto-perf/cperf_ops.c b/app/test-crypto-perf/cperf_ops.c index 514ca69334..8f320099dd 100644 --- a/app/test-crypto-perf/cperf_ops.c +++ b/app/test-crypto-perf/cperf_ops.c @@ -13,7 +13,7 @@ cperf_set_ops_null_cipher(struct rte_crypto_op **ops, uint16_t nb_ops, struct rte_cryptodev_sym_session *sess, const struct cperf_options *options, const struct cperf_test_vector *test_vector __rte_unused, - uint16_t iv_offset __rte_unused) + uint16_t iv_offset __rte_unused, uint32_t *imix_idx) { uint16_t i; @@ -34,7 +34,12 @@ cperf_set_ops_null_cipher(struct rte_crypto_op **ops, dst_buf_offset); /* cipher parameters */ - sym_op->cipher.data.length = options->test_buffer_size; + if (options->imix_distribution_count) { + sym_op->cipher.data.length = + options->imix_buffer_sizes[*imix_idx]; + *imix_idx = (*imix_idx + 1) % options->pool_sz; + } else + sym_op->cipher.data.length = options->test_buffer_size; sym_op->cipher.data.offset = 0; } @@ -47,7 +52,7 @@ cperf_set_ops_null_auth(struct rte_crypto_op **ops, uint16_t nb_ops, struct rte_cryptodev_sym_session *sess, const struct cperf_options *options, const struct cperf_test_vector *test_vector __rte_unused, - uint16_t iv_offset __rte_unused) + uint16_t iv_offset __rte_unused, uint32_t *imix_idx) { uint16_t i; @@ -68,7 +73,12 @@ cperf_set_ops_null_auth(struct rte_crypto_op **ops, dst_buf_offset); /* auth parameters */ - sym_op->auth.data.length = options->test_buffer_size; + if (options->imix_distribution_count) { + sym_op->auth.data.length = + options->imix_buffer_sizes[*imix_idx]; + *imix_idx = (*imix_idx + 1) % options->pool_sz; + } else + sym_op->auth.data.length = options->test_buffer_size; sym_op->auth.data.offset = 0; } @@ -81,7 +91,7 @@ cperf_set_ops_cipher(struct rte_crypto_op **ops, uint16_t nb_ops, struct rte_cryptodev_sym_session *sess, const struct cperf_options *options, const struct cperf_test_vector *test_vector, - uint16_t iv_offset) + uint16_t iv_offset, uint32_t *imix_idx) { uint16_t i; @@ -102,12 +112,17 @@ cperf_set_ops_cipher(struct rte_crypto_op **ops, dst_buf_offset); /* cipher parameters */ + if (options->imix_distribution_count) { + sym_op->cipher.data.length = + options->imix_buffer_sizes[*imix_idx]; + *imix_idx = (*imix_idx + 1) % options->pool_sz; + } else + sym_op->cipher.data.length = options->test_buffer_size; + if (options->cipher_algo == RTE_CRYPTO_CIPHER_SNOW3G_UEA2 || options->cipher_algo == RTE_CRYPTO_CIPHER_KASUMI_F8 || options->cipher_algo == RTE_CRYPTO_CIPHER_ZUC_EEA3) - sym_op->cipher.data.length = options->test_buffer_size << 3; - else - sym_op->cipher.data.length = options->test_buffer_size; + sym_op->cipher.data.length <<= 3; sym_op->cipher.data.offset = 0; } @@ -132,7 +147,7 @@ cperf_set_ops_auth(struct rte_crypto_op **ops, uint16_t nb_ops, struct rte_cryptodev_sym_session *sess, const struct cperf_options *options, const struct cperf_test_vector *test_vector, - uint16_t iv_offset) + uint16_t iv_offset, uint32_t *imix_idx) { uint16_t i; @@ -197,12 +212,17 @@ cperf_set_ops_auth(struct rte_crypto_op **ops, } + if (options->imix_distribution_count) { + sym_op->auth.data.length = + options->imix_buffer_sizes[*imix_idx]; + *imix_idx = (*imix_idx + 1) % options->pool_sz; + } else + sym_op->auth.data.length = options->test_buffer_size; + if (options->auth_algo == RTE_CRYPTO_AUTH_SNOW3G_UIA2 || options->auth_algo == RTE_CRYPTO_AUTH_KASUMI_F9 || options->auth_algo == RTE_CRYPTO_AUTH_ZUC_EIA3) - sym_op->auth.data.length = options->test_buffer_size << 3; - else - sym_op->auth.data.length = options->test_buffer_size; + sym_op->auth.data.length <<= 3; sym_op->auth.data.offset = 0; } @@ -227,7 +247,7 @@ cperf_set_ops_cipher_auth(struct rte_crypto_op **ops, uint16_t nb_ops, struct rte_cryptodev_sym_session *sess, const struct cperf_options *options, const struct cperf_test_vector *test_vector, - uint16_t iv_offset) + uint16_t iv_offset, uint32_t *imix_idx) { uint16_t i; @@ -248,12 +268,17 @@ cperf_set_ops_cipher_auth(struct rte_crypto_op **ops, dst_buf_offset); /* cipher parameters */ + if (options->imix_distribution_count) { + sym_op->cipher.data.length = + options->imix_buffer_sizes[*imix_idx]; + *imix_idx = (*imix_idx + 1) % options->pool_sz; + } else + sym_op->cipher.data.length = options->test_buffer_size; + if (options->cipher_algo == RTE_CRYPTO_CIPHER_SNOW3G_UEA2 || options->cipher_algo == RTE_CRYPTO_CIPHER_KASUMI_F8 || options->cipher_algo == RTE_CRYPTO_CIPHER_ZUC_EEA3) - sym_op->cipher.data.length = options->test_buffer_size << 3; - else - sym_op->cipher.data.length = options->test_buffer_size; + sym_op->cipher.data.length <<= 3; sym_op->cipher.data.offset = 0; @@ -293,12 +318,17 @@ cperf_set_ops_cipher_auth(struct rte_crypto_op **ops, rte_pktmbuf_iova_offset(buf, offset); } + if (options->imix_distribution_count) { + sym_op->auth.data.length = + options->imix_buffer_sizes[*imix_idx]; + *imix_idx = (*imix_idx + 1) % options->pool_sz; + } else + sym_op->auth.data.length = options->test_buffer_size; + if (options->auth_algo == RTE_CRYPTO_AUTH_SNOW3G_UIA2 || options->auth_algo == RTE_CRYPTO_AUTH_KASUMI_F9 || options->auth_algo == RTE_CRYPTO_AUTH_ZUC_EIA3) - sym_op->auth.data.length = options->test_buffer_size << 3; - else - sym_op->auth.data.length = options->test_buffer_size; + sym_op->auth.data.length <<= 3; sym_op->auth.data.offset = 0; } @@ -332,7 +362,7 @@ cperf_set_ops_aead(struct rte_crypto_op **ops, uint16_t nb_ops, struct rte_cryptodev_sym_session *sess, const struct cperf_options *options, const struct cperf_test_vector *test_vector, - uint16_t iv_offset) + uint16_t iv_offset, uint32_t *imix_idx) { uint16_t i; /* AAD is placed after the IV */ @@ -356,7 +386,12 @@ cperf_set_ops_aead(struct rte_crypto_op **ops, dst_buf_offset); /* AEAD parameters */ - sym_op->aead.data.length = options->test_buffer_size; + if (options->imix_distribution_count) { + sym_op->aead.data.length = + options->imix_buffer_sizes[*imix_idx]; + *imix_idx = (*imix_idx + 1) % options->pool_sz; + } else + sym_op->aead.data.length = options->test_buffer_size; sym_op->aead.data.offset = 0; sym_op->aead.aad.data = rte_crypto_op_ctod_offset(ops[i], diff --git a/app/test-crypto-perf/cperf_ops.h b/app/test-crypto-perf/cperf_ops.h index d155a43a86..29e109f2a3 100644 --- a/app/test-crypto-perf/cperf_ops.h +++ b/app/test-crypto-perf/cperf_ops.h @@ -23,7 +23,7 @@ typedef int (*cperf_populate_ops_t)(struct rte_crypto_op **ops, uint16_t nb_ops, struct rte_cryptodev_sym_session *sess, const struct cperf_options *options, const struct cperf_test_vector *test_vector, - uint16_t iv_offset); + uint16_t iv_offset, uint32_t *imix_idx); struct cperf_op_fns { cperf_sessions_create_t sess_create; diff --git a/app/test-crypto-perf/cperf_options.h b/app/test-crypto-perf/cperf_options.h index da4fb47c31..b0c9f446d7 100644 --- a/app/test-crypto-perf/cperf_options.h +++ b/app/test-crypto-perf/cperf_options.h @@ -13,6 +13,7 @@ #define CPERF_BUFFER_SIZE ("buffer-sz") #define CPERF_SEGMENT_SIZE ("segment-sz") #define CPERF_DESC_NB ("desc-nb") +#define CPERF_IMIX ("imix") #define CPERF_DEVTYPE ("devtype") #define CPERF_OPTYPE ("optype") @@ -73,6 +74,7 @@ struct cperf_options { uint32_t total_ops; uint32_t segment_sz; uint32_t test_buffer_size; + uint32_t *imix_buffer_sizes; uint32_t nb_descriptors; uint16_t nb_qps; @@ -122,6 +124,8 @@ struct cperf_options { /* pmd-cyclecount specific options */ uint32_t pmdcc_delay; + uint32_t imix_distribution_list[MAX_LIST]; + uint8_t imix_distribution_count; }; void diff --git a/app/test-crypto-perf/cperf_options_parsing.c b/app/test-crypto-perf/cperf_options_parsing.c index ae0d7fb234..7a5aa06a67 100644 --- a/app/test-crypto-perf/cperf_options_parsing.c +++ b/app/test-crypto-perf/cperf_options_parsing.c @@ -29,6 +29,7 @@ usage(char *progname) " --total-ops N: set the number of total operations performed\n" " --burst-sz N: set the number of packets per burst\n" " --buffer-sz N: set the size of a single packet\n" + " --imix N: set the distribution of packet sizes\n" " --segment-sz N: set the size of the segment to use\n" " --desc-nb N: set number of descriptors for each crypto device\n" " --devtype TYPE: set crypto device type to use\n" @@ -215,6 +216,8 @@ parse_list(const char *arg, uint32_t *list, uint32_t *min, uint32_t *max) char *token; uint32_t number; uint8_t count = 0; + uint32_t temp_min; + uint32_t temp_max; char *copy_arg = strdup(arg); @@ -233,8 +236,8 @@ parse_list(const char *arg, uint32_t *list, uint32_t *min, uint32_t *max) goto err_list; list[count++] = number; - *min = number; - *max = number; + temp_min = number; + temp_max = number; } else goto err_list; @@ -255,14 +258,19 @@ parse_list(const char *arg, uint32_t *list, uint32_t *min, uint32_t *max) list[count++] = number; - if (number < *min) - *min = number; - if (number > *max) - *max = number; + if (number < temp_min) + temp_min = number; + if (number > temp_max) + temp_max = number; token = strtok(NULL, ","); } + if (min) + *min = temp_min; + if (max) + *max = temp_max; + free(copy_arg); return count; @@ -358,6 +366,29 @@ parse_segment_sz(struct cperf_options *opts, const char *arg) return 0; } +static int +parse_imix(struct cperf_options *opts, const char *arg) +{ + int ret; + + ret = parse_list(arg, opts->imix_distribution_list, + NULL, NULL); + if (ret < 0) { + RTE_LOG(ERR, USER1, "failed to parse imix distribution\n"); + return -1; + } + + opts->imix_distribution_count = ret; + + if (opts->imix_distribution_count <= 1) { + RTE_LOG(ERR, USER1, "imix distribution should have " + "at least two entries\n"); + return -1; + } + + return 0; +} + static int parse_desc_nb(struct cperf_options *opts, const char *arg) { @@ -694,6 +725,7 @@ static struct option lgopts[] = { { CPERF_SEGMENT_SIZE, required_argument, 0, 0 }, { CPERF_DESC_NB, required_argument, 0, 0 }, + { CPERF_IMIX, required_argument, 0, 0 }, { CPERF_DEVTYPE, required_argument, 0, 0 }, { CPERF_OPTYPE, required_argument, 0, 0 }, @@ -758,6 +790,7 @@ cperf_options_default(struct cperf_options *opts) */ opts->segment_sz = 0; + opts->imix_distribution_count = 0; strncpy(opts->device_type, "crypto_aesni_mb", sizeof(opts->device_type)); opts->nb_qps = 1; @@ -807,6 +840,7 @@ cperf_opts_parse_long(int opt_idx, struct cperf_options *opts) { CPERF_OPTYPE, parse_op_type }, { CPERF_SESSIONLESS, parse_sessionless }, { CPERF_OUT_OF_PLACE, parse_out_of_place }, + { CPERF_IMIX, parse_imix }, { CPERF_TEST_FILE, parse_test_file }, { CPERF_TEST_NAME, parse_test_name }, { CPERF_CIPHER_ALGO, parse_cipher_algo }, @@ -945,6 +979,14 @@ cperf_options_check(struct cperf_options *options) return -EINVAL; } + if ((options->imix_distribution_count != 0) && + (options->imix_distribution_count != + options->buffer_size_count)) { + RTE_LOG(ERR, USER1, "IMIX distribution must have the same " + "number of buffer sizes\n"); + return -EINVAL; + } + if (options->test == CPERF_TEST_TYPE_VERIFY && options->test_file == NULL) { RTE_LOG(ERR, USER1, "Define path to the file with test" @@ -997,6 +1039,13 @@ cperf_options_check(struct cperf_options *options) return -EINVAL; } + if (options->test == CPERF_TEST_TYPE_VERIFY && + options->imix_distribution_count > 0) { + RTE_LOG(ERR, USER1, "IMIX is not allowed when " + "using the verify test.\n"); + return -EINVAL; + } + if (options->op_type == CPERF_CIPHER_THEN_AUTH) { if (options->cipher_op != RTE_CRYPTO_CIPHER_OP_ENCRYPT && options->auth_op != diff --git a/app/test-crypto-perf/cperf_test_latency.c b/app/test-crypto-perf/cperf_test_latency.c index 8565d08361..c9c98dc50d 100644 --- a/app/test-crypto-perf/cperf_test_latency.c +++ b/app/test-crypto-perf/cperf_test_latency.c @@ -126,6 +126,7 @@ cperf_latency_test_runner(void *arg) struct cperf_latency_ctx *ctx = arg; uint16_t test_burst_size; uint8_t burst_size_idx = 0; + uint32_t imix_idx = 0; static int only_once; @@ -200,7 +201,8 @@ cperf_latency_test_runner(void *arg) (ctx->populate_ops)(ops, ctx->src_buf_offset, ctx->dst_buf_offset, burst_size, ctx->sess, ctx->options, - ctx->test_vector, iv_offset); + ctx->test_vector, iv_offset, + &imix_idx); tsc_start = rte_rdtsc_precise(); diff --git a/app/test-crypto-perf/cperf_test_pmd_cyclecount.c b/app/test-crypto-perf/cperf_test_pmd_cyclecount.c index 54a2e55ae0..8f76160819 100644 --- a/app/test-crypto-perf/cperf_test_pmd_cyclecount.c +++ b/app/test-crypto-perf/cperf_test_pmd_cyclecount.c @@ -141,6 +141,7 @@ pmd_cyclecount_bench_ops(struct pmd_cyclecount_state *state, uint32_t cur_op, uint32_t iter_ops_needed = RTE_MIN(state->opts->nb_descriptors, iter_ops_left); uint32_t cur_iter_op; + uint32_t imix_idx = 0; for (cur_iter_op = 0; cur_iter_op < iter_ops_needed; cur_iter_op += test_burst_size) { @@ -165,7 +166,8 @@ pmd_cyclecount_bench_ops(struct pmd_cyclecount_state *state, uint32_t cur_op, state->ctx->dst_buf_offset, burst_size, state->ctx->sess, state->opts, - state->ctx->test_vector, iv_offset); + state->ctx->test_vector, iv_offset, + &imix_idx); #ifdef CPERF_LINEARIZATION_ENABLE /* Check if source mbufs require coalescing */ @@ -190,6 +192,7 @@ pmd_cyclecount_build_ops(struct pmd_cyclecount_state *state, uint32_t iter_ops_needed, uint16_t test_burst_size) { uint32_t cur_iter_op; + uint32_t imix_idx = 0; for (cur_iter_op = 0; cur_iter_op < iter_ops_needed; cur_iter_op += test_burst_size) { @@ -214,7 +217,8 @@ pmd_cyclecount_build_ops(struct pmd_cyclecount_state *state, state->ctx->dst_buf_offset, burst_size, state->ctx->sess, state->opts, - state->ctx->test_vector, iv_offset); + state->ctx->test_vector, iv_offset, + &imix_idx); } return 0; } diff --git a/app/test-crypto-perf/cperf_test_throughput.c b/app/test-crypto-perf/cperf_test_throughput.c index eae284e1d1..8766d6e9b0 100644 --- a/app/test-crypto-perf/cperf_test_throughput.c +++ b/app/test-crypto-perf/cperf_test_throughput.c @@ -92,6 +92,7 @@ cperf_throughput_test_runner(void *test_ctx) struct cperf_throughput_ctx *ctx = test_ctx; uint16_t test_burst_size; uint8_t burst_size_idx = 0; + uint32_t imix_idx = 0; static int only_once; @@ -165,7 +166,7 @@ cperf_throughput_test_runner(void *test_ctx) ctx->dst_buf_offset, ops_needed, ctx->sess, ctx->options, ctx->test_vector, - iv_offset); + iv_offset, &imix_idx); /** * When ops_needed is smaller than ops_enqd, the diff --git a/app/test-crypto-perf/cperf_test_verify.c b/app/test-crypto-perf/cperf_test_verify.c index 49bd105801..9134b921e0 100644 --- a/app/test-crypto-perf/cperf_test_verify.c +++ b/app/test-crypto-perf/cperf_test_verify.c @@ -236,6 +236,7 @@ cperf_verify_test_runner(void *test_ctx) uint64_t i; uint16_t ops_unused = 0; + uint32_t imix_idx = 0; struct rte_crypto_op *ops[ctx->options->max_burst_size]; struct rte_crypto_op *ops_processed[ctx->options->max_burst_size]; @@ -289,7 +290,7 @@ cperf_verify_test_runner(void *test_ctx) (ctx->populate_ops)(ops, ctx->src_buf_offset, ctx->dst_buf_offset, ops_needed, ctx->sess, ctx->options, - ctx->test_vector, iv_offset); + ctx->test_vector, iv_offset, &imix_idx); /* Populate the mbuf with the test vector, for verification */ diff --git a/app/test-crypto-perf/main.c b/app/test-crypto-perf/main.c index 21b868db3f..83a9d7b73c 100644 --- a/app/test-crypto-perf/main.c +++ b/app/test-crypto-perf/main.c @@ -5,6 +5,8 @@ #include #include +#include +#include #include #include #ifdef RTE_LIBRTE_PMD_CRYPTO_SCHEDULER @@ -508,13 +510,45 @@ main(int argc, char **argv) i++; } - /* Get first size from range or list */ - if (opts.inc_buffer_size != 0) - opts.test_buffer_size = opts.min_buffer_size; - else - opts.test_buffer_size = opts.buffer_size_list[0]; + if (opts.imix_distribution_count != 0) { + uint8_t buffer_size_count = opts.buffer_size_count; + uint16_t distribution_total[buffer_size_count]; + uint32_t op_idx; + uint32_t test_average_size = 0; + const uint32_t *buffer_size_list = opts.buffer_size_list; + const uint32_t *imix_distribution_list = opts.imix_distribution_list; + + opts.imix_buffer_sizes = rte_malloc(NULL, + sizeof(uint32_t) * opts.pool_sz, + 0); + /* + * Calculate accumulated distribution of + * probabilities per packet size + */ + distribution_total[0] = imix_distribution_list[0]; + for (i = 1; i < buffer_size_count; i++) + distribution_total[i] = imix_distribution_list[i] + + distribution_total[i-1]; + + /* Calculate a random sequence of packet sizes, based on distribution */ + for (op_idx = 0; op_idx < opts.pool_sz; op_idx++) { + uint16_t random_number = rte_rand() % + distribution_total[buffer_size_count - 1]; + for (i = 0; i < buffer_size_count; i++) + if (random_number < distribution_total[i]) + break; + + opts.imix_buffer_sizes[op_idx] = buffer_size_list[i]; + } + + /* Calculate average buffer size for the IMIX distribution */ + for (i = 0; i < buffer_size_count; i++) + test_average_size += buffer_size_list[i] * + imix_distribution_list[i]; + + opts.test_buffer_size = test_average_size / + distribution_total[buffer_size_count - 1]; - while (opts.test_buffer_size <= opts.max_buffer_size) { i = 0; RTE_LCORE_FOREACH_SLAVE(lcore_id) { @@ -533,14 +567,45 @@ main(int argc, char **argv) rte_eal_wait_lcore(lcore_id); i++; } + } else { /* Get next size from range or list */ if (opts.inc_buffer_size != 0) - opts.test_buffer_size += opts.inc_buffer_size; - else { - if (++buffer_size_idx == opts.buffer_size_count) - break; - opts.test_buffer_size = opts.buffer_size_list[buffer_size_idx]; + opts.test_buffer_size = opts.min_buffer_size; + else + opts.test_buffer_size = opts.buffer_size_list[0]; + + while (opts.test_buffer_size <= opts.max_buffer_size) { + i = 0; + RTE_LCORE_FOREACH_SLAVE(lcore_id) { + + if (i == nb_cryptodevs) + break; + + cdev_id = enabled_cdevs[i]; + + rte_eal_remote_launch(cperf_testmap[opts.test].runner, + ctx[cdev_id], lcore_id); + i++; + } + i = 0; + RTE_LCORE_FOREACH_SLAVE(lcore_id) { + + if (i == nb_cryptodevs) + break; + rte_eal_wait_lcore(lcore_id); + i++; + } + + /* Get next size from range or list */ + if (opts.inc_buffer_size != 0) + opts.test_buffer_size += opts.inc_buffer_size; + else { + if (++buffer_size_idx == opts.buffer_size_count) + break; + opts.test_buffer_size = + opts.buffer_size_list[buffer_size_idx]; + } } } @@ -579,7 +644,7 @@ err: for (i = 0; i < nb_cryptodevs && i < RTE_CRYPTO_MAX_DEVS; i++) rte_cryptodev_stop(enabled_cdevs[i]); - + rte_free(opts.imix_buffer_sizes); free_test_vector(t_vec, &opts); printf("\n"); diff --git a/doc/guides/tools/cryptoperf.rst b/doc/guides/tools/cryptoperf.rst index 7e12677088..75ce46d6ab 100644 --- a/doc/guides/tools/cryptoperf.rst +++ b/doc/guides/tools/cryptoperf.rst @@ -171,6 +171,20 @@ The following are the appication command-line options: is the maximum size (i.e. ``--buffer-sz 16:2:32``) * List of values, up to 32 values, separated in commas (i.e. ``--buffer-sz 32,64,128``) +* ``--imix `` + + Set the distribution of packet sizes. + + A list of weights must be passed, containing the same number of items than buffer-sz, + so each item in this list will be the weight of the packet size on the same position + in the buffer-sz parameter (a list have to be passed in that parameter). + + Example: + + To test a distribution of 20% packets of 64 bytes, 40% packets of 100 bytes and 40% packets + of 256 bytes, the command line would be: ``--buffer-sz 64,100,256 --imix 20,40,40``. + Note that the weights do not have to be percentages, so using ``--imix 1,2,2`` would result + in the same distribution * ``--segment-sz `` -- 2.20.1