the heuristics that limits kernel memory on a cpu server to
a fixed amout (64MB + size for page tables) makes using devdraw
impractical.
if *imagemaxmb= is specified, we can assume that the draw device
will be used so we want to get a reasonable amount (30% default)
of kernel memory.
link status not working on 82567 was due to wrong phy number
used. instead of hardcoding the phy numbers, probe the phys
by reading id1 and id2 registers (code stolen from ethermii).
on the 82567, reading any phy register just gives 0 back.
however, the card works just fine and no action is required
to (re-)start auto negotiation. so we add maclproc() which just
reads the speed setting and link status from the mac status
register instead of reading the phy registers.
we'v probably seen this symptom on other cards (link: 0) like
82566. we should test if we can make link status work on
these cards as well by just using the maclproc().
rx pool exhaustion causes the system to deadlock when netbooted.
queue management should (etheroq) already makes sure the systen
can keep up with the data thowing away buffers.
icansleep() violates the lock ordering due to the following cases:
rbfree(): ilock(Rbpool.Lock) -> wakeup(): spli(), lock(Rbpool.Rendez)
sleep(): splhi(), lock(Rbpool.Rendez) -> icansleep(): ilock(Rbpool.Lock)
erik fixed this moving the wakeup() out of the ilock() in rbfree(),
but i think it is an error to try acquiering a ilock in sleeps wait
condition function in general.
so this is what we do:
in the icansleep() function, we check for the *real* event we care about;
that is, if theres a buffer available in the Rbpool. this is to handle
the case when rbfree() makes a buffer available *before* it sees us
setting p->starve = 1.
p->starve is now just used to gate rbfree() from calling wakeup() as
an optimization.
this might cause spurious wakeups but they are not a problem. missed
wakeups is the thing we have to prevent.
this patch consists of two bits of work submitted as one
patch.
the first bit fixed a "pacing" problem, where a tcp connection
rate-limited by the reading process would experience 10%
of the expected throughput, and could even get into live
lock. it was noticed at the time of this initial work that
the stack often sent tiny grams. some good bits from nix'
original tcp were merged in. the test program
/n/sources/contrib/quanstro/tcptest.c
will verify that under most conditions, a reader-paced connection
now gets the expected throughput. expected arguments
would be
tcptest -s1 -n 5000 -l
the second bit is a first step in preparing tcp to handle
modest (1-2MB) bandwidth-delay products. the strategy
was to completely implement NewReno. the testing network
was a 7/35/70ms by 100Mbit wan emulator with 0/.05/.1% loss.
here are the performance comparisons from the changes after
the first round "old" to the submitted patch "new". the
smallest improvement was 80%, the largest was 11x.
loss% rtt old new
0.10 7 4.40 7.85
0.10 35 0.88 1.79
0.10 70 0.47 0.84
0.05 7 4.80 9.38
0.05 35 1.00 2.02
0.05 70 0.52 1.77
0.01 7 5.33 11.87
0.01 35 1.14 10.97
0.01 70 0.54 4.75
0.00 7 4.49 11.92
0.00 35 1.04 11.35
0.00 70 0.58 10.56
since the diff is not very easy to read, i wrote a small
paper detailing the changes
http://www.quanstro.net/plan9/tcp/tcp.pdf
- erik
the cmd box is not part of the alt display hirarchy. for command
typing to show the box in alt display, we call pldraw() on it
in eresized() to initialize its cmd->b image so it knows where to
draw itself on typing.
the driver should work for standard sdhc
(see http://www.sdcard.org/) controllers,
but matches for the ricoh controller only
as it was the only one i have for testing.
if LocalX or ArgX is a package, the store into
a element should *not* type convert. so when taking
the index reference, we have to carry over the type.
empty href="" attribute in base-tag causes the page to break.
while at it, handle empty attributes in other parts of the
code as well. (mostly stuff like id, name shouldnt be empty)
