Re: [dpdk-dev] [PATCH v5 2/2] eal: add additional info if core mask too long

[David Hunt <david.hunt@intel.com>]

Hi David,

On 2/11/2021 5:45 PM, David Marchand wrote:
> On Thu, Sep 23, 2021 at 1:03 PM David Hunt <david.hunt@intel.com> wrote:
>> If the user requests to use an lcore above 128 using -c,
>> the eal will exit with "EAL: invalid coremask syntax" and
>> very little else useful information.
>>
>> This patch adds some extra information suggesting to use --lcores
>> so that physical cores above RTE_MAX_LCORE (default 128) can be
>> used. This is achieved by using the --lcores option by mapping
>> the logical cores in the application to physical cores.
>>
>> For example, if "-c 0x300000000000000000000000000000000" is
>> used, we see the following additional output on the command line:
>>
>> EAL: lcore 128 >= RTE_MAX_LCORE (128)
>> EAL: lcore 129 >= RTE_MAX_LCORE (128)
>> EAL: to use high physical core ids , please use --lcores to
>> map them to lcore ids below RTE_MAX_LCORE,
>> EAL:     e.g. --lcores 0@128,1@129
>>
>> Signed-off-by: David Hunt <david.hunt@intel.com>
>> Acked-by: Bruce Richardson <bruce.richardson@intel.com>
>> ---
>> changes in v3
>>     * added this patch to the set. Addresses the changes for
>>       the -c option.
>> changes in v4
>>     * fixed buffer overrun in populating lcore array.
>>     * switched from strlcpy to strdup due to a clang error.
>> changes in v5
>>     * replaced strdup and frees with a const char *, as we
>>       just need to keep track of original pointer location.
>>     * reverted err: usage to return -1, as no free() needed.
>>     * other minod code cleanups.
>> ---
>> ---
>>   lib/eal/common/eal_common_options.c | 47 ++++++++++++++++++++++++-----
>>   1 file changed, 40 insertions(+), 7 deletions(-)
>>
>> diff --git a/lib/eal/common/eal_common_options.c b/lib/eal/common/eal_common_options.c
>> index 72735e0b09..7f715e4c15 100644
>> --- a/lib/eal/common/eal_common_options.c
>> +++ b/lib/eal/common/eal_common_options.c
>> @@ -750,10 +750,12 @@ check_core_list(int *lcores, unsigned int count)
>>   static int
>>   eal_parse_coremask(const char *coremask, int *cores)
>>   {
>> -       unsigned count = 0;
>> +       unsigned int count = 0;
>>          int i, j, idx;
>>          int val;
>>          char c;
>> +       int lcores[RTE_MAX_LCORE];
>> +       const char *coremask_orig = coremask;
>>
>>          for (idx = 0; idx < RTE_MAX_LCORE; idx++)
>>                  cores[idx] = -1;
>> @@ -770,29 +772,60 @@ eal_parse_coremask(const char *coremask, int *cores)
>>          i = strlen(coremask);
>>          while ((i > 0) && isblank(coremask[i - 1]))
>>                  i--;
>> -       if (i == 0)
>> +       if (i == 0) {
>> +               RTE_LOG(ERR, EAL, "No lcores in coremask: [%s]\n",
>> +                               coremask_orig);
>>                  return -1;
>> +       }
>>
>> -       for (i = i - 1; i >= 0 && idx < RTE_MAX_LCORE; i--) {
>> +       for (i = i - 1; i >= 0; i--) {
> This loop exit condition changes here: this ensures that, once we
> leave the loop, i == -1.
> As a consequence... (see below)
>
>
>>                  c = coremask[i];
>>                  if (isxdigit(c) == 0) {
>>                          /* invalid characters */
>> +                       RTE_LOG(ERR, EAL, "invalid characters in coremask: [%s]\n",
>> +                                       coremask_orig);
>>                          return -1;
>>                  }
>>                  val = xdigit2val(c);
>> -               for (j = 0; j < BITS_PER_HEX && idx < RTE_MAX_LCORE; j++, idx++)
>> +               for (j = 0; j < BITS_PER_HEX; j++, idx++)
>>                  {
>>                          if ((1 << j) & val) {
>> -                               cores[idx] = count;
>> +                               if (count >= RTE_MAX_LCORE) {
>> +                                       RTE_LOG(ERR, EAL, "Too many lcores provided. Cannot exceed %d\n",
>> +                                                       RTE_MAX_LCORE);
>> +                                       return -1;
>> +                               }
>> +                               lcores[count] = idx;
>>                                  count++;
>>                          }
>>                  }
>>          }
> ... this loop below is dead code.


Sure, no need to loop. I'll take out the loop, and just check for the 
first two characters to be '0x', as they're already trimmed.


>>          for (; i >= 0; i--)
>> -               if (coremask[i] != '0')
>> +               if (coremask[i] != '0') {
>> +                       RTE_LOG(ERR, EAL, "invalid characters in coremask: [%s]\n",
>> +                                       coremask_orig);
> Nit: capital letter.


Many other instances of 'invalid' in this file, will I change them all 
to "Invalid", or just this one?


>
>>                          return -1;
>> -       if (count == 0)
>> +               }
>> +       if (count == 0) {
>> +               RTE_LOG(ERR, EAL, "No lcores in coremask: [%s]\n",
>> +                               coremask_orig);
>> +               return -1;
>> +       }
>> +
>> +       if (check_core_list(lcores, count))
>>                  return -1;
>> +
>> +       /*
>> +        * Now that we've gto a list of cores no longer than
> Same typo I commented on patch 1 for v4.

Will fix.


>
>
>> +        * RTE_MAX_LCORE, and no lcore in that list is greater
>> +        * than RTE_MAX_LCORE, populate the cores
>> +        * array and return.
>> +        */
>> +       do {
>> +               count--;
>> +               cores[lcores[count]] = count;
>> +       } while (count != 0);
>> +
>>          return 0;
>>   }
>>
>> --
>> 2.17.1
>>