On Wed, Nov 18, 2020 at 12:36 PM Randy Dunlap [off-list ref] wrote:

On 11/18/20 11:10 AM, Wei Wang wrote:

quoted

From: Paolo Abeni <pabeni@redhat.com>

this patch adds a new sysfs attribute to the network
device class. Said attribute is a bitmask that allows controlling
the threaded mode for all the napi instances of the given
network device.

The threaded mode can be switched only if related network device
is down.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Hannes Frederic Sowa <redacted>
Signed-off-by: Wei Wang <redacted>
Reviewed-by: Eric Dumazet <edumazet@google.com>

Hi,

Could someone describe the bitmask (is it a bit per instance of the
network device?).
And how to use the sysfs interface, please?

It is 1 bit per napi. Depending on the driver implementation, 1 napi
could correspond to 1 tx queue, or 1 rx queue, or 1 pair of tx/rx
queues.
To set bits in the bit mask, you could do:
echo 0-14 > /sys/class/net/<dev>/threaded
to set consecutive bits.
or:
echo 0,2,4,6,8 >  /sys/class/net/<dev>/threaded
to set individual bits.

To clear the bit mask, you could do:
echo > /sys/class/net/<dev>/threaded

quoted

---
 net/core/net-sysfs.c | 103 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 94fff0700bdd..df8dd25e5e4b 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c

thanks.
--
~Randy