thanks for replying michi, BTW how does a layer above network device driver manages skb cache? how can we tune this skb cache size? any idea? On Fri, Apr 17, 2009 at 2:01 PM, Devesh Sharma <devesh28@xxxxxxxxx> wrote: > Hi michi, > Its is using a TCP/IP protocol, program is Intel's MPI benchmark IMB, > and CPU is surely not a bottelneck because its Quad core Quad socket > machine with 64GB of physical mem. its a proprietary device for > Systems Area Networks used for cluster computing. But the main problem > that I have observed is, my device do not get any packets to post > during this data size thats why I am trying to look beyond my device > related functions. > > > On Fri, Apr 17, 2009 at 1:49 PM, Michael Blizek > <michi1@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote: >> Hi! >> >> On 11:03 Fri 17 Apr , Devesh Sharma wrote: >>> Hello list, >>> >>> I have written a network device driver, and to validate it, I am >>> running a bandwidth measurement tool on it, >>> I am encountering a strange drop in bandwidth when data size reaches >>> to 4096, bandwidth figures drop form 24 Mbps (for 2k data size) >>> to .43 Mbps. what can be the problem, the MTU of my device is 2044. Is >>> it some how related to functioning of hard_start_xmit? >> >> What program/protocol do you use for testing + what kind of device is >> this? The CPU is not a bottleneck, is it? >> >> -Michi >> -- >> programing a layer 3+4 network protocol for mesh networks >> see http://michaelblizek.twilightparadox.com >> >> > -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
