> You stated in an earlier message you copied the data when you caclulated
> the TCPIP checksum? No you say you don't. Perhaps I misunderstood.
We do a single copy/checksum from user space. You have to do the copy because
the packet may not be DMAable, may not be aligned for most PCI hardware a
> You just told us earlier in the thread that NetWare does direct zero
> copy DMA but thats only half the story obviously. Up until the era of
> Gigabit Ethernet cards there were almost no PCI cards available that
> would do scatter/gather so obviously netware wasn't doing zero copy
> either.
Net
Alan Cox wrote:
>
> We dont copy for checksumming. We fold the single user space copy and the
> checksum operation into one path, because on any modern CPU it costs precisely
> the same to copy as to copy/checksum.
You stated in an earlier message you copied the data when you caclulated
the TC
> > There arent copies all over the case for the paths that occur. Like 99.999%
> > of the time. Fragmented packets dont happen except for NFS (which is a rather
> > broken protocol anyway).
>
> There are.
You forgot to cite them
> > the socket operations from user space use file-> dereferen
Alan Cox wrote:
>
> > > Sounds like Linux - one DMA and one copy to user space.
> >
> > Alan, Please. I'm in your code and there are copies all over the
> > place. I agree you have a "fast path" for most stuff, but there's all
>
> There arent copies all over the case for the paths that occur
> "Jeff" == Jeff V Merkey <[EMAIL PROTECTED]> writes:
Jeff> **ALL** Netware network drivers support a scatter/gather
Jeff> proramming interface, whether the hardware does or not. In
Jeff> NetWare, the drivers get passed a fragment list in what's called
Jeff> an ECB (Event Control Block). It
> > Sounds like Linux - one DMA and one copy to user space.
>
> Alan, Please. I'm in your code and there are copies all over the
> place. I agree you have a "fast path" for most stuff, but there's all
There arent copies all over the case for the paths that occur. Like 99.999%
of the time. Frag
**ALL** Netware network drivers support a scatter/gather proramming
interface, whether the hardware does or not. In NetWare, the drivers
get passed a fragment list in what's called an ECB (Event Control
Block). It's the drivers responsiblity to assemble the fragment lists.
We did it this way t
> "Jeff" == Jeff V Merkey <[EMAIL PROTECTED]> writes:
[since you like to forward things after sending me a private email, I'll
do the same].
Jeff> I wrote the SMP ODI networking layer in NetWare that used today by
Jeff> over 90,000,000 NetWare users. I also wrote the SMP LLC8022
Jeff> Stack
On Sat, Sep 02, 2000 at 10:35:11PM +0100, Alan Cox wrote:
> > to MANOS, and what a mess indeed. In NetWare, the only time data ever
> > gets copied from incoming packets is:
> >
> > 1. A copy to userspace at a stream head.
> > 2. An incoming write that gets copied into the file cache.
>
> Soun
> "Jeff" == Jeff V Merkey <[EMAIL PROTECTED]> writes:
Jeff> all over the place that increases latency. Not to mention the
Jeff> overhead of the type of interrupt and trap gates that suck up
Jeff> about 50 clocks to fetch the IDT, PDE, and GDT tables for every
Jeff> interrupt. NetWare copies
Alan Cox wrote:
>
> > to MANOS, and what a mess indeed. In NetWare, the only time data ever
> > gets copied from incoming packets is:
> >
> > 1. A copy to userspace at a stream head.
> > 2. An incoming write that gets copied into the file cache.
>
> Sounds like Linux - one DMA and one copy t
> to MANOS, and what a mess indeed. In NetWare, the only time data ever
> gets copied from incoming packets is:
>
> 1. A copy to userspace at a stream head.
> 2. An incoming write that gets copied into the file cache.
Sounds like Linux - one DMA and one copy to user space.
> Reads from cache
> "Jeff" == Jeff V Merkey <[EMAIL PROTECTED]> writes:
Jeff, could you start by learning to quote email and not send a full
copy of the entire email you reply to (read rfc1855).
Jeff> The entire Linux Network subsystem needs an overhaul. The code
Jeff> copies data all over the place. I am at
The entire Linux Network subsystem needs an overhaul. The code copies
data all over the place. I am at present pulling it apart and porting it
to MANOS, and what a mess indeed. In NetWare, the only time data ever
gets copied from incoming packets is:
1. A copy to userspace at a stream head.
2.
> "Ingo" == Ingo Molnar <[EMAIL PROTECTED]> writes:
Ingo> On Sat, 2 Sep 2000, Dan Maas wrote:
>> There are various other tricks that can be done to speed up network
>> servers, like passing files directly from the buffer cache to the
>> network card. This one is currently frowned upon by the
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