Point taken. I would have to fragmenting it in to 2 when > 32K on the main processor side and using the firmware on the NIC to break it down to MTU size. Thanks Alan -----Original Message----- From: Eble, Dan [mailto:DanE@aiinet.com] Sent: Tuesday, July 22, 2003 8:05 AM To: linux-net@vger.kernel.org Cc: 'Alan Shih' Subject: RE: Limit skb to be less than 64K with TSO It seems the best solution is to split large buffers when they reach the driver, for the reason that if your hardware had a much smaller maximum, you would not want to change it globally, so why should you change it globally for 32kB? > -----Original Message----- > From: Alan Shih [mailto:alan@storlinksemi.com] > Sent: Tuesday, July 22, 2003 10:54 AM > To: Eble, Dan > Subject: RE: Limit skb to be less than 64K with TSO > > > Dan, > > Thanks for your reply. I am writing a driver (+ firmware on > a smart NIC). > The SKB's comes from upper layers. TSO is tcp/ip > segmentation offloading > that 2.6 supports. > > The problem comes in when TSO is on, the system throws me 64K > SKB's maximum > which my hardware cannot take. There seems to be a few > places I can tap in > but not quite sure which method is appropriate (may be not > doable other than > my ignorance). > > 1. at alloc_skb (if I limit at 32K, I may break applications?) > 2. when I receive skb from queue_xmit, the driver needs to > break it up. > 3. figure out where in VFS that allow 64K and size it down. > > TIA > > Alan > > -----Original Message----- > From: Eble, Dan [mailto:DanE@aiinet.com] > Sent: Tuesday, July 22, 2003 5:19 AM > To: 'Alan Shih' > Subject: RE: Limit skb to be less than 64K with TSO > > > I don't know what TSO is, but I'd like to try to help, so if you could > please explain the origin of these skbs that concern you, I > would have a > clearer picture of what's going on. Are these skbs allocated > by higher > layers of the kernel networking code and passed to your driver for > transmission? > > > -----Original Message----- > > From: Alan Shih [mailto:alan@storlinksemi.com] > > Sent: Monday, July 21, 2003 10:21 PM > > To: linux-net@vger.kernel.org > > Subject: Limit skb to be less than 64K with TSO > > > > > > Hi all, > > > > Is there a way to limit skb to be 32KB Max? I am working with > > a hardware > > that has a small scratch SRAM for a smart NIC (I am using it > > to do TSO). > > It's great for speed but cannot handle large skb (>32K). > > > > TIA > > > > Alan > > > > - > > : send the line "unsubscribe > > linux-net" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
