motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-05 00:33:55 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

target-arm: Implement WFE as a yield operation

Browse source 
Implement WFE to yield our timeslice to the next CPU.
This avoids slowdowns in multicore configurations caused
by one core busy-waiting on a spinlock which can't possibly
be unlocked until the other core has an opportunity to run.
This speeds up my test case A15 dual-core boot by a factor
of three (though it is still four or five times slower than
a single-core boot).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1393339545-22111-1-git-send-email-peter.maydell@linaro.org
Reviewed-by: Richard Henderson <rth@twiddle.net>
Tested-by: Rob Herring <rob.herring@linaro.org>
This commit is contained in:
Peter Maydell 2014-03-10 14:56:30 +00:00
parent 2b194951c5
commit 72c1d3af6e
5 changed files with 19 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

6
target-arm/translate.c
View file

@ -3939,6 +3939,9 @@ static void gen_nop_hint(DisasContext *s, int val)
s->is_jmp = DISAS_WFI;
break;
case 2: /* wfe */
gen_set_pc_im(s, s->pc);
s->is_jmp = DISAS_WFE;
break;
case 4: /* sev */
case 5: /* sevl */
/* TODO: Implement SEV, SEVL and WFE. May help SMP performance. */
@ -10857,6 +10860,9 @@ static inline void gen_intermediate_code_internal(ARMCPU *cpu,
case DISAS_WFI:
gen_helper_wfi(cpu_env);
break;
case DISAS_WFE:
gen_helper_wfe(cpu_env);
break;
case DISAS_SWI:
gen_exception(EXCP_SWI);
break;