netdev - Re: [PATCH net-next 1/2] selftests: drv-net: fix RPS mask handling in toeplitz test

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Message-ID: <363dee6c-3a02-4f76-aa6d-46382fa41df9@nvidia.com>
Date: Mon, 12 Jan 2026 09:58:25 +0200
From: Gal Pressman <gal@...dia.com>
To: Willem de Bruijn <willemdebruijn.kernel@...il.com>,
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
 Andrew Lunn <andrew+netdev@...n.ch>, netdev@...r.kernel.org
Cc: Shuah Khan <shuah@...nel.org>, Willem de Bruijn <willemb@...gle.com>,
 Petr Machata <petrm@...dia.com>, Coco Li <lixiaoyan@...gle.com>,
 linux-kselftest@...r.kernel.org, Nimrod Oren <noren@...dia.com>
Subject: Re: [PATCH net-next 1/2] selftests: drv-net: fix RPS mask handling in
 toeplitz test

On 12/01/2026 5:43, Willem de Bruijn wrote:
> Gal Pressman wrote:
>> The toeplitz.py test passed the hex mask without "0x" prefix (e.g.,
>> "300" for CPUs 8,9). The toeplitz.c strtoul() call wrongly parsed this
>> as decimal 300 (0x12c) instead of hex 0x300.
>>
>> Use separate format strings for sysfs (plain hex via format()) and
>> command line (prefixed hex via hex()).
>>
>> Fixes: 9cf9aa77a1f6 ("selftests: drv-net: hw: convert the Toeplitz test to Python")
>> Reviewed-by: Nimrod Oren <noren@...dia.com>
>> Signed-off-by: Gal Pressman <gal@...dia.com>
> 
> Reviewed-by: Willem de Bruijn <willemb@...gle.com>
> 
>> ---
>>  tools/testing/selftests/drivers/net/hw/toeplitz.py | 9 ++++++---
>>  1 file changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/tools/testing/selftests/drivers/net/hw/toeplitz.py b/tools/testing/selftests/drivers/net/hw/toeplitz.py
>> index d2db5ee9e358..7a9af4af1838 100755
>> --- a/tools/testing/selftests/drivers/net/hw/toeplitz.py
>> +++ b/tools/testing/selftests/drivers/net/hw/toeplitz.py
>> @@ -94,14 +94,17 @@ def _configure_rps(cfg, rps_cpus):
>>      mask = 0
>>      for cpu in rps_cpus:
>>          mask |= (1 << cpu)
>> -    mask = hex(mask)[2:]
>> +
>> +    # sysfs expect hex without '0x' prefix, toeplitz.c needs the prefix
>> +    mask_sysfs = format(mask, 'x')
> 
> A particular reason not to use the existing slicing?
> 
>> +    mask_cmdline = hex(mask)
>>  
>>      # Set RPS bitmap for all rx queues
>>      for rps_file in glob.glob(f"/sys/class/net/{cfg.ifname}/queues/rx-*/rps_cpus"):
>>          with open(rps_file, "w", encoding="utf-8") as fp:
>> -            fp.write(mask)
>> +            fp.write(mask_sysfs)
> 
> Alternatively 
> 
> -    mask = hex(mask)[2:]
> +    mask = hex(mask)
> 
> - fp.write(mask)
> + fp.write(mask[2:])
> 
> The comment that sysfs and toeplitz.c expect different input is
> definitely helpful.

Will take your suggestion, thanks.