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Date: Tue, 19 Feb 2013 10:57:54 +0100 From: Rafał Miłecki <zajec5@...il.com> To: David Laight <David.Laight@...lab.com> Cc: David Miller <davem@...emloft.net>, Larry.Finger@...inger.net, linville@...driver.com, linux-wireless@...r.kernel.org, netdev@...r.kernel.org, bittorf@...ebottle.com, stable@...r.kernel.org Subject: Re: [PATCH] b43: Increase number of RX DMA slots 2013/2/19 David Laight <David.Laight@...lab.com>: >> > Bastian Bittorf reported that some of the silent freezes on a Linksys WRT54G >> > were due to overflow of the RX DMA ring buffer, which was created with 64 >> > slots. That finding reminded me that I was seeing similar crashed on a netbook, >> > which also has a relatively slow processor. After increasing the number of >> > slots to 128, runs on the netbook that previously failed now worked; however, >> > I found that 109 slots had been used in one test. For that reason, the number >> > of slots is being increased to 256. > > Surely the driver should work even if all the RX buffers get filled? > Increasing the number of buffers is just hiding the issue. > A burst of 300 back to back small packets probably fills the 256 slots. > > I realise that dropping frames isn't ideal, and that small numbers > of buffers can make it impossible to receive long fragmented IP > messages. but increasing the number of buffers doesn't seem to > be the best fix for a 'silent freeze'. > > It might be that the driver would be more robust if it only ever > put rx buffers into all but one of the ring slots. That's what I said ;) I have this on my TODO, but I need to resolve my issues with ethernet first. -- Rafał -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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