[lc-devel] 0.24pre8 test results and future requirements

[John R M. <jm...@st...>]

bob, I've tried oM, it's neat but not something i'm interested in ATM 
since it was a little unstable to me.  I'd wait until 2.6 or 2.8 and just 
merge them there.  I'm actually hoping linus will merge grsecurity and 
ccache into 2.6 by the end of its testing phase, but we'd need ccache on 
rmap and a 2.6 grsec first.  oM is something i'm not too worried about 
right now.

One thing I'm worried about though is that the ccache patched kernel 
doesn't seem to like my Nvidia card.  Since Nvidia cards are common, this 
needs to be fixed.  I'm not sure if it's a ccache bug or an nvdriver bug, 
or just a kernel bug that ccache brings out.  I think ccache will work 
better in 2.4.22 and .23 for these though (it worked in .21 with my 
nvdriver) so it may just be kernel.

There's also the 2.4 ccache (and oM, and many other patches) issue that 
`iptables -t nat -I POSTROUTING -o eth0 -j MASQUERADE` doesn't seem to 
work due to 'target problem'.  Yes, the masq module is compiled.  Try 
it.  Try to fix this, since it's kind of important, NAT being popular and 
all.

Anyway, here's my test results for a kernel compile.  I think the 
measurement for using ccache was a bit high time-wise because I DID swap 
some, and so I am going to redo the test later with no swap enabled.  
Eventually I need to do some 20 tests under each condition.  I'm still 
shakey about lzo so I didn't compile its init instruction into my kernel; 
however, i've discovered that compalg=WK4x4 and compalg=WKdm work 
properly!  o.o!

The trivial bug on line 309 I think of proc.c that spews so much about 
algorithm like 13000 or something is from being called by swapout.c and 
trying to update the stats for the algorithm that an UNCOMPRESSED page is 
using when it swaps out.  Oops.  Need to make a NO_ALGORITHM_IDX entry 
load at boot and use that as a dump for uncompressed stats.  Also need to 
rewrite the page allocation code and so on.

I'm not going to be writing anymore code in this for now.  Go ahead and 
write some without me.  I don't know how to work with modules, so none of 
that from me.

Move the LZO, WKdm, and WK4x4 algs into modules and allow them to 
optionally be compiled in (but not default alg if loaded as modules).  
Give them the interface of the core central compression library (same as 
zlib).

If there is no standard interface for the compression library functions,
write one on top of the kernel's zlib and also place it on top of WKdm,
WK4x4, and LZO when you dump them into the library core.  Also, try to 
insert a registration system init function on top of the kernel's zlib 
interface, and call its init before initing compressed page cache if it 
is compiled in to the kernel for both compression and decompression.

Someone needs to check WKdm and WK4x4 to see if they are really workable 
for >4k pages.

 --Bluefox Icy