From 89e7997622038f82115f34dbb4ea382e02bed163 Mon Sep 17 00:00:00 2001 From: Alan Wu Date: Tue, 30 Jul 2019 21:36:05 -0400 Subject: Combine call info and cache to speed up method invocation To perform a regular method call, the VM needs two structs, `rb_call_info` and `rb_call_cache`. At the moment, we allocate these two structures in separate buffers. In the worst case, the CPU needs to read 4 cache lines to complete a method call. Putting the two structures together reduces the maximum number of cache line reads to 2. Combining the structures also saves 8 bytes per call site as the current layout uses separate two pointers for the call info and the call cache. This saves about 2 MiB on Discourse. This change improves the Optcarrot benchmark at least 3%. For more details, see attached bugs.ruby-lang.org ticket. Complications: - A new instruction attribute `comptime_sp_inc` is introduced to calculate SP increase at compile time without using call caches. At compile time, a `TS_CALLDATA` operand points to a call info struct, but at runtime, the same operand points to a call data struct. Instruction that explicitly define `sp_inc` also need to define `comptime_sp_inc`. - MJIT code for copying call cache becomes slightly more complicated. - This changes the bytecode format, which might break existing tools. [Misc #16258] --- vm_insnhelper.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'vm_insnhelper.h') diff --git a/vm_insnhelper.h b/vm_insnhelper.h index 9f09d4ab5e..99555fd4ed 100644 --- a/vm_insnhelper.h +++ b/vm_insnhelper.h @@ -166,7 +166,7 @@ enum vm_regan_acttype { #ifndef MJIT_HEADER #define CALL_SIMPLE_METHOD() do { \ rb_snum_t x = leaf ? INSN_ATTR(width) : 0; \ - rb_snum_t y = attr_width_opt_send_without_block(0, 0); \ + rb_snum_t y = attr_width_opt_send_without_block(0); \ rb_snum_t z = x - y; \ ADD_PC(z); \ DISPATCH_ORIGINAL_INSN(opt_send_without_block); \ -- cgit v1.2.1