Messages in this thread | | | Date | Tue, 9 Apr 1996 11:00:08 -0700 (MST) | From | "Howard C. Tyler" <> | Subject | Slow PPP |
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Poor Linus, your head is not going to like this.
My Amd586-133 suffers from the slow-PPP problems when it is run with a 33Mhz clock in 4X mode, but hasn't dropped a packet since I changed it to a 50Mhz clock and 3X mode and both L1 and L2 caches in write-back mode.
Since changing the clocking, I haven't had any problems with any version since 1.3.81 thru 1.3.85. My old PPP problems seemed to be missing bytes, as frames where being dropped due to FCS errors.
I sure that you know, the PPP driver does not support throttling of the sender (see: ppp_tty_room). The driver assumes that it will always be fast enough to accept anything sent to it. NCFTP has reported >10Kb/sec thru-put receiving uncompressed source files over a 24K baud connection. If I ever get connected at 28.8K, this could be 20% faster. The receive buffer is allocated as 1584 bytes, which could be filled in 0.15 sec. at 10Kb/sec. If there is no room in the receive buffer, the driver just drops them into the bit-bucket!
I'm using ppp-2.2.0e, gcc-2.7.2, libc-5.2.18.
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