Richard Henderson <richard.hender...@linaro.org> writes:
> Compute the value using straight division and bounds,
> rather than a loop. Pass in tb_size rather than reading
> from tcg_init_ctx.code_gen_buffer_size,
>
> Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
> ---
> tcg/region.c | 29 ++++++++++++-----------------
> 1 file changed, 12 insertions(+), 17 deletions(-)
>
> diff --git a/tcg/region.c b/tcg/region.c
> index bd81b35359..b44246e1aa 100644
> --- a/tcg/region.c
> +++ b/tcg/region.c
> @@ -363,38 +363,33 @@ void tcg_region_reset_all(void)
> tcg_region_tree_reset_all();
> }
>
> -static size_t tcg_n_regions(unsigned max_cpus)
> +static size_t tcg_n_regions(size_t tb_size, unsigned max_cpus)
> {
> #ifdef CONFIG_USER_ONLY
> return 1;
> #else
> + size_t n_regions;
> +
> /*
> * It is likely that some vCPUs will translate more code than others,
> * so we first try to set more regions than max_cpus, with those regions
> * being of reasonable size. If that's not possible we make do by evenly
> * dividing the code_gen_buffer among the vCPUs.
> */
> - size_t i;
> -
> /* Use a single region if all we have is one vCPU thread */
> if (max_cpus == 1 || !qemu_tcg_mttcg_enabled()) {
> return 1;
> }
>
> - /* Try to have more regions than max_cpus, with each region being >= 2
> MB */
> - for (i = 8; i > 0; i--) {
> - size_t regions_per_thread = i;
> - size_t region_size;
> -
> - region_size = tcg_init_ctx.code_gen_buffer_size;
> - region_size /= max_cpus * regions_per_thread;
> -
> - if (region_size >= 2 * 1024u * 1024) {
> - return max_cpus * regions_per_thread;
> - }
> + /*
> + * Try to have more regions than max_cpus, with each region being >= 2
> MB.
> + * If we can't, then just allocate one region per vCPU thread.
> + */
> + n_regions = tb_size / (2 * MiB);
> + if (n_regions <= max_cpus) {
> + return max_cpus;
> }
> - /* If we can't, then just allocate one region per vCPU thread */
> - return max_cpus;
> + return MIN(n_regions, max_cpus * 8);
> #endif
> }
This is so much easier to follow now ;-)
Reviewed-by: Alex Bennée <alex.ben...@linaro.org>
--
Alex Bennée
