> -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx] > Sent: Wednesday, February 3, 2016 11:06 AM > To: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > Cc: davem@xxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; KY Srinivasan > <kys@xxxxxxxxxxxxx>; olaf@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx > Subject: Re: [PATCH net-next] hv_netvsc: Increase delay for > RNDIS_STATUS_NETWORK_CHANGE > > Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> writes: > > >> -----Original Message----- > >> From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx] > >> Sent: Wednesday, February 3, 2016 8:06 AM > >> To: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > >> Cc: davem@xxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; KY Srinivasan > >> <kys@xxxxxxxxxxxxx>; olaf@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > >> driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx > >> Subject: Re: [PATCH net-next] hv_netvsc: Increase delay for > >> RNDIS_STATUS_NETWORK_CHANGE > >> > >> Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> writes: > >> > >> > We simulates a link down period for > RNDIS_STATUS_NETWORK_CHANGE > >> message to > >> > trigger DHCP renew. User daemons may need multiple seconds to > trigger > >> the > >> > link down event. (e.g. ifplugd: 5sec, network-manager: 4sec.) So update > >> > this link down period to 10 sec to properly trigger DHCP renew. > >> > > >> > >> I probably don't follow: why do we need sucha a delay? If (with real > >> hardware) you plug network cable out and in one second you plug it in > >> you'll get DHCP renewed, right? > >> > >> When I introduced RNDIS_STATUS_NETWORK_CHANGE handling by > >> emulating a > >> pair of up/down events I put 2 second delay to make link_watch happy > (as > >> we only handle 1 event per second there) but 10 seconds sounds to much > >> to me. > > > > In the test on Hyper-V, our software on host side wants to trigger DHCP > > renew by sending only a RNDIS_STATUS_NETWORK_CHANGE message to > > a guest without physically unplug the cable. But, this message didn't trigger > > DHCP renew within 2 seconds. The VM is Centos 7.1 using > Networkmanager, > > which needs 4 seconds after link down to renew IP. Some daemon, like > > ifplugd, needs 5 sec to renew. That's why we increase the simulated link > > down time for RNDIS_STATUS_NETWORK_CHANGE message. > > Yes, I understand the motivation but sorry if I was unclear with my > question. I meant to say that with physical network adapters it's > possible to trigger same two events by plugging your cable out and then > plugging it back in and it is certailnly doable in less than 10 > seconds. NetworkManager or whoever is supposed to handle these events > and we don't really care how fast -- I think that 4 or 5 seconds > mentioned above is just an observation. (forgot mailing lists in my last reply.... re-sending...) Our test failed (i.e. not triggering DHCP renew) with existing 2sec delay. According to the ifplugd man page, it ignores link down time <5sec: http://linux.die.net/man/8/ifplugd -d | --delay-down= SECS Specify delay for deconfiguring interface (default: 5) Networkmanager also has a waiting period (4sec). Thanks, - Haiyang _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
