Re: [dpdk-dev] [PATCH v2] eal: add option --master-lcore

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

Hi Thomas,
Few questions/comments below.
Konstantin

> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Thomas Monjalon
> Sent: Tuesday, November 04, 2014 9:41 PM
> To: dev@dpdk.org
> Subject: [dpdk-dev] [PATCH v2] eal: add option --master-lcore
> 
> From: Simon Kuenzer <simon.kuenzer@neclab.eu>
> 
> Enable users to specify the lcore id that is used as master lcore.
> 
> Signed-off-by: Simon Kuenzer <simon.kuenzer@neclab.eu>
> Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>
> ---
> 
> changes in v2:
> - rebase on HEAD including common options for BSD and Linux
> - use strtol() instead of atoi() to check syntax errors
> - unit tests
> 
>  app/test/test.c                             |  1 +
>  app/test/test_eal_flags.c                   | 49 +++++++++++++++++++++++++++++
>  lib/librte_eal/bsdapp/eal/eal.c             |  7 +++++
>  lib/librte_eal/common/eal_common_options.c  | 31 ++++++++++++++++++
>  lib/librte_eal/common/include/eal_options.h |  2 ++
>  lib/librte_eal/linuxapp/eal/eal.c           |  7 +++++
>  6 files changed, 97 insertions(+)
> 
> diff --git a/app/test/test.c b/app/test/test.c
> index 9bee6bb..2fecff5 100644
> --- a/app/test/test.c
> +++ b/app/test/test.c
> @@ -82,6 +82,7 @@ do_recursive_call(void)
>  	} actions[] =  {
>  			{ "run_secondary_instances", test_mp_secondary },
>  			{ "test_missing_c_flag", no_action },
> +			{ "test_master_lcore_flag", no_action },
>  			{ "test_missing_n_flag", no_action },
>  			{ "test_no_hpet_flag", no_action },
>  			{ "test_whitelist_flag", no_action },
> diff --git a/app/test/test_eal_flags.c b/app/test/test_eal_flags.c
> index 21e6cca..45020b8 100644
> --- a/app/test/test_eal_flags.c
> +++ b/app/test/test_eal_flags.c
> @@ -520,6 +520,49 @@ test_missing_c_flag(void)
>  }
> 
>  /*
> + * Test --master-lcore option with matching coremask
> + */
> +static int
> +test_master_lcore_flag(void)
> +{
> +#ifdef RTE_EXEC_ENV_BSDAPP
> +	/* BSD target doesn't support prefixes at this point */
> +	const char * prefix = "";
> +#else
> +	char prefix[PATH_MAX], tmp[PATH_MAX];
> +	if (get_current_prefix(tmp, sizeof(tmp)) == NULL) {
> +		printf("Error - unable to get current prefix!\n");
> +		return -1;
> +	}
> +	snprintf(prefix, sizeof(prefix), "--file-prefix=%s", tmp);
> +#endif
> +
> +	/* --master-lcore flag but no value */
> +	const char *argv1[] = { prgname, prefix, mp_flag, "-n", "1", "-c", "3", "--master-lcore"};
> +	/* --master-lcore flag with invalid value */
> +	const char *argv2[] = { prgname, prefix, mp_flag, "-n", "1", "-c", "3", "--master-lcore", "-1"};
> +	/* --master-lcore flag with invalid value */
> +	const char *argv3[] = { prgname, prefix, mp_flag, "-n", "1", "-c", "3", "--master-lcore", "X"};
> +	/* master lcore not in coremask */
> +	const char *argv4[] = { prgname, prefix, mp_flag, "-n", "1", "-c", "3", "--master-lcore", "2"};
> +	/* valid value */
> +	const char *argv5[] = { prgname, prefix, mp_flag, "-n", "1", "-c", "3", "--master-lcore", "1"};
> +
> +	if (launch_proc(argv1) == 0
> +			|| launch_proc(argv2) == 0
> +			|| launch_proc(argv3) == 0
> +			|| launch_proc(argv4) == 0) {
> +		printf("Error - process ran without error with wrong --master-lcore\n");
> +		return -1;
> +	}
> +	if (launch_proc(argv5) != 0) {
> +		printf("Error - process did not run ok with valid --master-lcore\n");
> +		return -1;
> +	}
> +	return 0;
> +}
> +
> +/*
>   * Test that the app doesn't run without the -n flag. In all cases
>   * should give an error and fail to run.
>   * Since -n is not compulsory for MP, we instead use --no-huge and --no-shconf
> @@ -1214,6 +1257,12 @@ test_eal_flags(void)
>  		return ret;
>  	}
> 
> +	ret = test_master_lcore_flag();
> +	if (ret < 0) {
> +		printf("Error in test_master_lcore_flag()\n");
> +		return ret;
> +	}
> +
>  	ret = test_missing_n_flag();
>  	if (ret < 0) {
>  		printf("Error in test_missing_n_flag()\n");
> diff --git a/lib/librte_eal/bsdapp/eal/eal.c b/lib/librte_eal/bsdapp/eal/eal.c
> index ca99cb9..c764fec 100644
> --- a/lib/librte_eal/bsdapp/eal/eal.c
> +++ b/lib/librte_eal/bsdapp/eal/eal.c
> @@ -354,6 +354,13 @@ eal_parse_args(int argc, char **argv)
>  		if (opt == '?')
>  			return -1;
> 
> +		if (opt == OPT_MASTER_LCORE_NUM && !coremask_ok) {
> +			RTE_LOG(ERR, EAL, "please specify the master lcore id"
> +				"after specifying the coremask\n");
> +			eal_usage(prgname);
> +			return -1;
> +		}
> +
>  		ret = eal_parse_common_option(opt, optarg, &internal_config);
>  		/* common parser is not happy */
>  		if (ret < 0) {
> diff --git a/lib/librte_eal/common/eal_common_options.c b/lib/librte_eal/common/eal_common_options.c
> index 7a5d55e..9166ea1 100644
> --- a/lib/librte_eal/common/eal_common_options.c
> +++ b/lib/librte_eal/common/eal_common_options.c
> @@ -64,6 +64,7 @@ eal_short_options[] =
>  const struct option
>  eal_long_options[] = {
>  	{OPT_HUGE_DIR, 1, 0, OPT_HUGE_DIR_NUM},
> +	{OPT_MASTER_LCORE, 1, 0, OPT_MASTER_LCORE_NUM},
>  	{OPT_PROC_TYPE, 1, 0, OPT_PROC_TYPE_NUM},
>  	{OPT_NO_SHCONF, 0, 0, OPT_NO_SHCONF_NUM},
>  	{OPT_NO_HPET, 0, 0, OPT_NO_HPET_NUM},
> @@ -163,6 +164,27 @@ eal_parse_coremask(const char *coremask)
>  	return 0;
>  }
> 
> +/* Changes the lcore id of the master thread */
> +static int
> +eal_parse_master_lcore(const char *arg)
> +{
> +	long master_lcore;
> +	char *parsing_end;
> +	struct rte_config *cfg = rte_eal_get_configuration();
> +
> +	errno = 0;
> +	master_lcore = strtol(arg, &parsing_end, 0);
> +	if (errno || parsing_end == arg)
> +		return -1;

Why not: "errno || parsing_end[0] != 0"
?

Otherwise something like "1blah" would be considered as valid input.

> +
> +	if (!(master_lcore >= 0 && master_lcore < RTE_MAX_LCORE))
> +		return -1;

If negative values are not allowed, then why not:

unsigned long master_lcore;
...
master_lcore = strtoul(...)
...
if(master_clore > RTE_MAX_LCORE)
    return -1;   

> +	if (cfg->lcore_role[master_lcore] != ROLE_RTE)
> +		return -1;
> +	cfg->master_lcore = master_lcore;
> +	return 0;
> +}
> +
>  static int
>  eal_parse_syslog(const char *facility, struct internal_config *conf)
>  {
> @@ -320,6 +342,14 @@ eal_parse_common_option(int opt, const char *optarg,
>  		conf->process_type = eal_parse_proc_type(optarg);
>  		break;
> 
> +	case OPT_MASTER_LCORE_NUM:
> +		if (eal_parse_master_lcore(optarg) < 0) {
> +			RTE_LOG(ERR, EAL, "invalid parameter for --"
> +					OPT_MASTER_LCORE "\n");
> +			return -1;
> +		}
> +		break;
> +
>  	case OPT_VDEV_NUM:
>  		if (rte_eal_devargs_add(RTE_DEVTYPE_VIRTUAL,
>  				optarg) < 0) {
> @@ -364,6 +394,7 @@ eal_common_usage(void)
>  	       "[--proc-type primary|secondary|auto]\n\n"
>  	       "EAL common options:\n"
>  	       "  -c COREMASK  : A hexadecimal bitmask of cores to run on\n"
> +	       "  --"OPT_MASTER_LCORE" ID: Core ID that is used as master\n"
>  	       "  -n NUM       : Number of memory channels\n"
>  	       "  -v           : Display version information on startup\n"
>  	       "  -m MB        : memory to allocate (see also --"OPT_SOCKET_MEM")\n"
> diff --git a/lib/librte_eal/common/include/eal_options.h b/lib/librte_eal/common/include/eal_options.h
> index 22819ec..deb872d 100644
> --- a/lib/librte_eal/common/include/eal_options.h
> +++ b/lib/librte_eal/common/include/eal_options.h
> @@ -43,6 +43,8 @@ enum {
>  	OPT_LONG_MIN_NUM = 256,
>  #define OPT_HUGE_DIR    "huge-dir"
>  	OPT_HUGE_DIR_NUM = OPT_LONG_MIN_NUM,
> +#define OPT_MASTER_LCORE "master-lcore"
> +	OPT_MASTER_LCORE_NUM,
>  #define OPT_PROC_TYPE   "proc-type"
>  	OPT_PROC_TYPE_NUM,
>  #define OPT_NO_SHCONF   "no-shconf"
> diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
> index 7a1d087..7fcb349 100644
> --- a/lib/librte_eal/linuxapp/eal/eal.c
> +++ b/lib/librte_eal/linuxapp/eal/eal.c
> @@ -550,6 +550,13 @@ eal_parse_args(int argc, char **argv)
>  		if (opt == '?')
>  			return -1;
> 
> +		if (opt == OPT_MASTER_LCORE_NUM && !coremask_ok) {
> +			RTE_LOG(ERR, EAL, "please specify the master lcore id"
> +				"after specifying the coremask\n");
> +			eal_usage(prgname);
> +			return -1;
> +		}
> +

I don't really like an idea of introducing strict order between -c and  "--master-lcore..
Can we move check for coremask_ok/ and assignment of cfg->master_lcore out of  
while (getopt_long(...)) loop?

>  		ret = eal_parse_common_option(opt, optarg, &internal_config);
>  		/* common parser is not happy */
>  		if (ret < 0) {
> --
> 2.1.3