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accel/tcg: increase default code gen buffer size for 64 bit

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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.bennee@linaro.org>
Tested-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Reviewed-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Message-Id: <20200228192415.19867-5-alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Alex Bennée 2020-02-28 19:24:15 +00:00 committed by Richard Henderson
parent 21f2f447ad
commit 600e17b261
1 changed files with 26 additions and 9 deletions
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35
accel/tcg/translate-all.c
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@ -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 \