Re: [PATCH v3] eal: update lcore-worker name due to high number of cores

[Kevin Traynor <ktraynor@redhat.com>]

On 26/09/2022 10:39, David Marchand wrote:
> Hello,
> 
> On Fri, Sep 23, 2022 at 9:06 AM Abdullah Ömer Yamaç
> <omer.yamac@ceng.metu.edu.tr> wrote:
>>
>> In this patch we suggest a new name for lcore-worker.
>> In case of more than 99 logical cores, name is truncated
>> (length is restricted to 16 characters, including the
>> terminating null byte ('\0')) and it makes hard to follow threads.
>>
>> Signed-off-by: Abdullah Ömer Yamaç <omer.yamac@ceng.metu.edu.tr>
>> Acked-by: Stephen Hemminger <stephen@networkplumber.org>
> 
> - Thanks, good catch.
> 
> Some comments though.
> What matters is the lcore index, not the core/lcore count.
> The commitlog could probably describe this better.
> 
> For example, this issue can be triggered with --lcores=0,10@1,100@2
> and here we only have three lcores.
> $ cat /proc/$(pidof dpdk-testpmd)/task/*/comm
> dpdk-testpmd
> eal-intr-thread
> rte_mp_handle
> lcore-worker-10
> lcore-worker-10
> telemetry-v2
> telemetry-v1
> 
> 
> And what do you think of following title:
> "eal: fix thread names for high order lcores"
> 
> Can you update the release notes?
> 
> 
> - Question to stable maintainers:
> Do you think we should backport this fix?
> As you can see below, this change affects EAL thread names, maybe some
> users are monitoring them based on the names...
> 

No strong opinion, but backporting will change the name for any user who 
looks at this and only fix an issue for users using lcore names 100+. So 
would be inclined not to backport unless someone complains it is causing 
a real issue for their use case.

> 
>>
>> ---
>> Cc: David Marchand <david.marchand@redhat.com>
>> ---
>>   lib/eal/freebsd/eal.c | 2 +-
>>   lib/eal/linux/eal.c   | 2 +-
>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/eal/freebsd/eal.c b/lib/eal/freebsd/eal.c
>> index ee5c929da8..a1bb5363b1 100644
>> --- a/lib/eal/freebsd/eal.c
>> +++ b/lib/eal/freebsd/eal.c
>> @@ -817,7 +817,7 @@ rte_eal_init(int argc, char **argv)
>>
>>                  /* Set thread_name for aid in debugging. */
>>                  snprintf(thread_name, sizeof(thread_name),
>> -                               "lcore-worker-%d", i);
>> +                               "rte-worker-%d", i);
>>                  rte_thread_setname(lcore_config[i].thread_id, thread_name);
>>
>>                  ret = pthread_setaffinity_np(lcore_config[i].thread_id,
>> diff --git a/lib/eal/linux/eal.c b/lib/eal/linux/eal.c
>> index 46bf52cef0..9a168b7773 100644
>> --- a/lib/eal/linux/eal.c
>> +++ b/lib/eal/linux/eal.c
>> @@ -1248,7 +1248,7 @@ rte_eal_init(int argc, char **argv)
>>
>>                  /* Set thread_name for aid in debugging. */
>>                  snprintf(thread_name, sizeof(thread_name),
>> -                       "lcore-worker-%d", i);
>> +                       "rte-worker-%d", i);
>>                  ret = rte_thread_setname(lcore_config[i].thread_id,
>>                                                  thread_name);
>>                  if (ret != 0)
>> --
>> 2.27.0
>>
> 
> Merci !
>