Re: [Tarantool-patches] [PATCH] Move txn from shema to a separate module (use C API instead of FFI)

[Konstantin Osipov <kostja.osipov@gmail.com>]

* Igor Munkin <imun@tarantool.org> [19/11/28 16:03]:
> LuaJIT v2.1 provides trace stitching feature (for more info see
> here[1]), so strictly saying, it doesn't kill JIT but yes, performance
> is nerfed comparing to traces recorded for an FFI code. I have no
> proofs/benchmarks for now, so it sounds kinda bullshit, but I look
> forward to make some in the nearest future.
> 
> Furthermore, FFI is not a silver bullet considering this issue[2].

I fully agree on all points, there is some buggy trace stitching,
there is an overhead of switching to Lua/C and back, 
(FFI is slower in Lua/C partly for this reason), and
FFI is not a silver bullet.

Despite all of the above we should be aiming at using FFI more,
not less, going forward, don't you agree?

What should be the rule of thumb in your opinion, ffi or
lua/c? 

> > plain Lua 5.3 and forget about grievances with LuaJIT altogether.
> 
> JIT is not the only killing feature provided by LuaJIT and
> infrastructure for Lua 5.1 is much richer.
> 
> > 
> > Nick Zavaritsky had a patch that would detect sandwich stacks in
> > runtime and assert. Nobody had time to look at it back then -
> 
> Could you please provide the issue/link for this changeset, I'll take a
> look on it with pleasure.

Nick Zavaritsky himself is the only link here, unfortunately.
Perhaps he has this patch in one of his personal branches. I
suggest someone contacts him :)

-- 
Konstantin Osipov, Moscow, Russia