[Tarantool-patches] [PATCH] tuple: make tuple_bless() compilable

[Igor Munkin]

Sergey,

I've checked the patch into master and 2.8.

On 22.10.21, Sergey Kaplun wrote:
> tuple_bless() uses a tail call to ffi.gc() with return to the caller.
> This tail call replaces the current (tuple_bless) frame with the frame
> of the callee (ffi.gc). When JIT tries to compile return from `ffi.gc()`
> to the frame below it aborts the trace recording with the error "NYI:
> return to lower frame".
> 
> This patch replaces the tail call with using additional local variable
> returned to the caller right after.
> ---
> 
> Actually, this patch become possible thanks to Michael Filonenko and his
> benchmarks of TDG runs with jit.dump() enabled. After analysis of this
> dump we realize that tuple_bless is not compiled. This uncompiled chunk
> of code leads to the JIT cancer for all possible workflows that use
> tuple_bless() (i.e. tuple:update() and tuple:upsert()). This change is
> really trivial, but adds almost x2 improvement of performance for
> tuple:update()/upsert() scenario. Hope, that this patch will be a
> stimulus for including benchmarks of our forward products like TDG to
> routine performance running with the corresponding profilers dumps.
> 
> Benchmarks:
> 
> Before patch:
> 
> Update:
> | Tarantool 2.10.0-beta1-90-g31594b427
> | type 'help' for interactive help
> | tarantool> local t = {}
> |            for i = 1, 1e6 do
> |                table.insert(t, box.tuple.new{'abc', 'def', 'ghi', 'abc'})
> |            end
> |            local clock = require"clock"
> |            local S = clock.proc()
> |            for i = 1, 1e6 do t[i]:update{{"=", 3, "xxx"}} end
> |            return clock.proc() - S;
> | ---
> | - 4.208298872
> 
> Upsert: 4.158661731
> 
> After patch:
> 
> Update:
> | Tarantool 2.10.0-beta1-90-g31594b427
> | type 'help' for interactive help
> | tarantool> local t = {}
> |            for i = 1, 1e6 do
> |                table.insert(t, box.tuple.new{'abc', 'def', 'ghi', 'abc'})
> |            end
> |            local clock = require"clock"
> |            local S = clock.proc()
> |            for i = 1, 1e6 do t[i]:update{{"=", 3, "xxx"}} end
> |            return clock.proc() - S;
> | ---
> | - 2.357670738
> 
> Upsert: 2.334134195
> 
> Branch: https://github.com/tarantool/tarantool/tree/skaplun/gh-noticket-tuple-bless-compile
> 
>  src/box/lua/tuple.lua | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 

<snipped>

> -- 
> 2.31.0
> 

-- 
Best regards,
IM