Hi,
tested and improves indeed startup speed.
On Mon, Nov 22, 2010 at 10:42:10PM +0300, Kirill Batuzov wrote:
> Move the last found TB to the head of the list so it will be found more
> quickly next time it will be looked for.
>
> Signed-off-by: Kirill Batuzov <batuz...@ispras.ru>
> Signed-off-by: Pavel Yushchenko <p...@ispras.ru>
> ---
> Hello. This patch gives significant boost to a used by us rather rich
> (for embedded one - featuring X-server, many daemons and applications)
> ARM-based system literally decreasing its boot to desktop time by TWO
> times! (Average number of traversed 'tb_phys_hash' entries in the main
> loop of the 'tb_find_slow' function reduced from 20 to 1.5.) We were
> able to shorten boot to login time by about 25% as well using Debian on
> versatilepb (no X-server, only basic system). Seems like kernel booting
> time is not affected. No problems were encountered during our
> experiments.
>
> We are looking forward for comments about this change and help with
> testing. Thanks in advance!
>
> cpu-exec.c | 5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/cpu-exec.c b/cpu-exec.c
> index 5d6dd51..55c4526 100644
> --- a/cpu-exec.c
> +++ b/cpu-exec.c
> @@ -161,6 +161,11 @@ static TranslationBlock *tb_find_slow(target_ulong pc,
> tb = tb_gen_code(env, pc, cs_base, flags, 0);
>
> found:
> + if (*ptb1) {
> + *ptb1 = tb->phys_hash_next;
> + tb->phys_hash_next = tb_phys_hash[h];
> + tb_phys_hash[h] = tb;
> + }
> /* we add the TB in the virtual pc hash table */
> env->tb_jmp_cache[tb_jmp_cache_hash_func(pc)] = tb;
> return tb;
