Messages in this thread | | | Date | Wed, 23 Jun 2004 14:00:23 +0200 | From | Martin Zwickel <> | Subject | Re: 2.6.7-rc2-mm2 udp multicast problem (sendto hangs) |
| |
On Wed, 23 Jun 2004 13:34:57 +0300 Denis Vlasenko <vda@port.imtp.ilyichevsk.odessa.ua> bubbled:
> On Wednesday 23 June 2004 12:56, Martin Zwickel wrote: > > if I use MSG_DONTWAIT with sendto, I get temporarily unavailable resources > > (many!): > > > > sendto(sendfd): Resource temporarily unavailable > > > > but isn't udp supposed to not block? > > Think about what will happen if you will try to spew > udp packets continuously: > > while(1) > sendto(...); > > They will pile up in queue and eventually it will fill up. > Then kernel may either drop excess packets silently > or return you EAGAIN.
Yes, but why does the kernel not send out the queue?(I don't know if the queue is empty or full when my sendto stops) Without MSG_DONTWAIT, sendto waits endlessly. But on what? Normally the kernel should put the queued packets on the line and accept new ones, or did I misunderstand this?
My program sends out many udp packets, and sometimes it just stops until the kernel receives a network packet or I access the local network(with arp command).
So if I run arp in an endless loop(while :; do arp; done), sendto runs smooth.
For me it smells like a bug ;)
Martin
-- MyExcuse: I'd love to help you -- it's just that the Boss won't let me near the computer.
Martin Zwickel <martin.zwickel@technotrend.de> Research & Development
TechnoTrend AG <http://www.technotrend.de> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |