Messages in this thread |  | | From | Bharath Madhavan <> | Subject | RE: Accelerated TCP/IP support from kernel | Date | Fri, 25 May 2001 09:51:39 -0400 |
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Hello all, We will most probably be looking into supporting Gig MACs and that is the reason why I was wondering if HW assist will help. We are talking of Gigs of network data (dont ask me the application!) I dont know about IPv6 support, we havent thought of that. But the point is, We can visualize a scenario where the processor is overworked and we want to relieve it off some of its load. To summarize the info I got from the mailing list, there are two conflicting views about this topic. 1. Protocol processing does not take much time compared to data processing and so the ZERO_COPY/HW_CHECKSUM feature in Linux currently is good enough. 2. The application maybe unique and heavy load that it may save the processor some bandwidth especially when several TCP connections needs to be maintained.
I am mainly looking into case 2, and just trying to see the amount of work that needs to go into this area. I am asking your expert opinions and find out if this is an easy job, if so can it be done to maintain compatability with older NICs too and able to move along easily with standard linux distributions. If the kernel can provide some hooks to "branch off" to a different set of drivers at the socket level, that will do the trick I think. Is this easy? Thanks a lot Bharath
-----Original Message----- From: David S. Miller [mailto:davem@redhat.com] Sent: Thursday, May 24, 2001 7:08 PM To: Bharath Madhavan Cc: 'linux-kernel@vger.kernel.org' Subject: RE: Accelerated TCP/IP support from kernel
Bharath Madhavan writes: > I guess 3c905c NIC supports HW checksumming. Is this true?
Yes.
> In this case, do we have any benchmarking for this card > with and without ZERO_COPY (and HW checksumming). I am eager to > know by how many times did the system throughput increase?
It doesn't matter with 100baseT cards, they are slow enough that even with the cpu doing the data copies the link may be easily saturated. What you will get is decreased CPU utilization.
You need to go to gigabit or faster link speeds to see any real throughput improvement.
Later, David S. Miller davem@redhat.com
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