On 5/25/21 9:45 AM, Alex Bennée wrote:
There are two justifications for making this change. The first is that
i386 emulation is typically for smaller machines where having a 1gb of
generated code is overkill for basic emulation. The second is the
propensity of self-modifying code (c.f. Doom/edit) utilised on i386
systems can trigger a rapid growth in invalidated and re-translated
buffers. This is seen in bug #283. Execution is still inefficient but
at least the host memory isn't so aggressively used up.
That said it's still really just a sticking plaster for user
convenience.
Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
Cc: Thomas Huth <th...@redhat.com>
Cc: 1896...@bugs.launchpad.net
---
accel/tcg/translate-all.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 640ff6e3e7..f442165674 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -951,9 +951,13 @@ static void page_lock_pair(PageDesc **ret_p1,
tb_page_addr_t phys1,
* Users running large scale system emulation may want to tweak their
* runtime setup via the tb-size control on the command line.
*/
+#ifdef TARGET_I386
+#define DEFAULT_CODE_GEN_BUFFER_SIZE_1 (32 * MiB)
+#else
#define DEFAULT_CODE_GEN_BUFFER_SIZE_1 (1 * GiB)
#endif
#endif
+#endif
#define DEFAULT_CODE_GEN_BUFFER_SIZE \
(DEFAULT_CODE_GEN_BUFFER_SIZE_1 < MAX_CODE_GEN_BUFFER_SIZE \
I'm not thrilled, as it is ultra-hacky.
(1) I've got a re-org of this code out for review:
https://patchew.org/QEMU/20210502231844.1977630-1-richard.hender...@linaro.org/
(2) I'm keen to reorg TCG such that it gets compiled once. There's currently
nothing standing in the way of that except work. But this would introduce a
use of a target-specific define for the first time into tcg/. I guess I could
leave the default sizing back in accel/tcg/ and pass in the default.
Other options?
r~
