diff options
| -rw-r--r-- | share/man/man4/man4.i386/ed.4 | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/share/man/man4/man4.i386/ed.4 b/share/man/man4/man4.i386/ed.4 index 208267afe1f..9a5f585b129 100644 --- a/share/man/man4/man4.i386/ed.4 +++ b/share/man/man4/man4.i386/ed.4 @@ -27,7 +27,7 @@ .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" -.\" $Id: ed.4,v 1.1 1995/10/18 08:44:29 deraadt Exp $ +.\" $Id: ed.4,v 1.2 1996/05/04 13:03:37 deraadt Exp $ .\" .Dd .Dt ED 4 i386 @@ -57,6 +57,42 @@ interface are: .It Novell NE1000 .It Novell NE2000 .El +.Sh DIAGNOSTICS +The DP8390 Ethernet chip implements a shared-memory ring-buffer +to store incoming packets. When this buffer overfills, the +.Nm +driver produces a message similar to the following: +.Pp +.Bl -tag -width -offset indent -compact +.It ed1: warning - receiver ring buffer overrun +.El +.Pp +The 16bit boards (8013 series) have 16k of memory as well as +fast memory access speed. Typical memory access speed on these +boards is about 4MB/second. These boards generally have no +problems keeping up with full ethernet speed and the ring-buffer +seldom overfills. +.Pp +However, the 8bit boards (3c503, and 8003) usually have +only 8k bytes of shared memory. This is only enough room for about +4 full-size (1500 byte) packets. This can sometimes be a problem, +especially on the original WD8003E and 3c503, because these +boards' shared-memory access speed is quite slow; typically +only about 1MB/second. The +overhead of this slow memory access, and the fact that there is +only room for 4 full-sized packets means that the ring-buffer +will occassionally overrun. When this happens, the board must +be reset to avoid a lockup problem in early revision 8390's. +Resetting the board causes all of the data in the ring-buffer +to be lost, requiring it to be retransmitted/received, congesting +the board further. Because of this, maximum throughput +on these boards is only about 400-600k per second. +.Pp +This problem is exasperated by NFS because the 8bit boards lack +sufficient memory to support the default 8k byte packets that NFS and +other protocols use as their default. If these cards must be used +with NFS, use the NFS -r and -w options to limit NFS's packet size. +4096k byte packets generally work. .Sh SEE ALSO .Xr ifconfig 8 , .Xr intro 4 , |