On Fri, Feb 28, 2020 at 8:24 PM Alex Bennée <alex.ben...@linaro.org> wrote:
> While 32mb is certainly usable a full system boot ends up flushing the > codegen buffer nearly 100 times. Increase the default on 64 bit hosts > to take advantage of all that spare memory. After this change I can > boot my tests system without any TB flushes. > > As we usually run more CONFIG_USER binaries at a time in typical usage > we aren't quite as profligate for user-mode code generation usage. We > also bring the static code gen defies to the same place to keep all > the reasoning in the comments together. > > Signed-off-by: Alex Bennée <alex.ben...@linaro.org> > Tested-by: Niek Linnenbank <nieklinnenb...@gmail.com> > Reviewed-by: Niek Linnenbank <nieklinnenb...@gmail.com> > > --- > v2 > - 2gb->1gb for system emulation > - split user and system emulation buffer sizes > --- > accel/tcg/translate-all.c | 35 ++++++++++++++++++++++++++--------- > 1 file changed, 26 insertions(+), 9 deletions(-) > > diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c > index 4ce5d1b3931..78914154bfc 100644 > --- a/accel/tcg/translate-all.c > +++ b/accel/tcg/translate-all.c > @@ -892,15 +892,6 @@ static void page_lock_pair(PageDesc **ret_p1, > tb_page_addr_t phys1, > } > } > > -#if defined(CONFIG_USER_ONLY) && TCG_TARGET_REG_BITS == 32 > -/* > - * For user mode on smaller 32 bit systems we may run into trouble > - * allocating big chunks of data in the right place. On these systems > - * we utilise a static code generation buffer directly in the binary. > - */ > -#define USE_STATIC_CODE_GEN_BUFFER > -#endif > - > /* Minimum size of the code gen buffer. This number is randomly chosen, > but not so small that we can't have a fair number of TB's live. */ > #define MIN_CODE_GEN_BUFFER_SIZE (1 * MiB) > @@ -929,7 +920,33 @@ static void page_lock_pair(PageDesc **ret_p1, > tb_page_addr_t phys1, > # define MAX_CODE_GEN_BUFFER_SIZE ((size_t)-1) > #endif > > +#if TCG_TARGET_REG_BITS == 32 > #define DEFAULT_CODE_GEN_BUFFER_SIZE_1 (32 * MiB) > +#ifdef CONFIG_USER_ONLY > +/* > + * For user mode on smaller 32 bit systems we may run into trouble > + * allocating big chunks of data in the right place. On these systems > + * we utilise a static code generation buffer directly in the binary. > + */ > +#define USE_STATIC_CODE_GEN_BUFFER > +#endif > +#else /* TCG_TARGET_REG_BITS == 64 */ > +#ifdef CONFIG_USER_ONLY > +/* > + * As user-mode emulation typically means running multiple instances > + * of the translator don't go too nuts with our default code gen > + * buffer lest we make things too hard for the OS. > + */ > +#define DEFAULT_CODE_GEN_BUFFER_SIZE_1 (128 * MiB) > +#else > +/* > + * We expect most system emulation to run one or two guests per host. > + * Users running large scale system emulation may want to tweak their > + * runtime setup via the tb-size control on the command line. > + */ > +#define DEFAULT_CODE_GEN_BUFFER_SIZE_1 (1 * GiB) > +#endif > +#endif > > #define DEFAULT_CODE_GEN_BUFFER_SIZE \ > (DEFAULT_CODE_GEN_BUFFER_SIZE_1 < MAX_CODE_GEN_BUFFER_SIZE \ > -- > 2.20.1 > > -- Niek Linnenbank
