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| author | Peter Maydell <peter.maydell@linaro.org> | 2014-03-10 14:56:30 +0000 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2014-03-10 14:56:30 +0000 |
| commit | 72c1d3af6e9c2745edfeaa71918a68bcee4b79db (patch) | |
| tree | d7d01966c8d75f5427fc2a9bce5994b17fe79253 /include | |
| parent | 2b194951c592ad670ddf3bc5764216408ade46f8 (diff) | |
| download | qemu-72c1d3af6e9c2745edfeaa71918a68bcee4b79db.tar.gz qemu-72c1d3af6e9c2745edfeaa71918a68bcee4b79db.tar.bz2 qemu-72c1d3af6e9c2745edfeaa71918a68bcee4b79db.zip | |
target-arm: Implement WFE as a yield operation
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/exec/cpu-defs.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/exec/cpu-defs.h b/include/exec/cpu-defs.h index 01cd8c7a2b..66a3d46938 100644 --- a/include/exec/cpu-defs.h +++ b/include/exec/cpu-defs.h @@ -59,6 +59,7 @@ typedef uint64_t target_ulong; #define EXCP_HLT 0x10001 /* hlt instruction reached */ #define EXCP_DEBUG 0x10002 /* cpu stopped after a breakpoint or singlestep */ #define EXCP_HALTED 0x10003 /* cpu is halted (waiting for external event) */ +#define EXCP_YIELD 0x10004 /* cpu wants to yield timeslice to another */ #define TB_JMP_CACHE_BITS 12 #define TB_JMP_CACHE_SIZE (1 << TB_JMP_CACHE_BITS) |