[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v4 25/26] tcg: Check for overflow via highwater
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH v4 25/26] tcg: Check for overflow via highwater mark |
Date: |
Wed, 30 Sep 2015 18:50:31 +0200 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On 2015-09-30 15:09, Richard Henderson wrote:
> We currently pre-compute an worst case code size for any TB, which
> works out to be 122kB. Since the average TB size is near 1kB, this
> wastes quite a lot of storage.
The code generation buffer is currently computed as 1/4 of the guest
RAM in softmmu mode (so 32MB for the default 128MB of RAM) or 32MB in
user mode. 122kB is therefore less than 0.4% of waster memory, I am not
therefore sure we need to add so much code just for that.
BTW, I wonder if it is really a good idea to scale the code generation
buffer with the size of the RAM, as the two do not seem that related. It
happens that at some point we don't really increases performances
anymore, and always defining it as 32MB might actually be a good idea.
Personally I am using a patch that limits it to 128MB.
--
Aurelien Jarno GPG: 4096R/1DDD8C9B
address@hidden http://www.aurel32.net
- [Qemu-devel] [PATCH v4 00/26] Do away with TB retranslation, Richard Henderson, 2015/10/08
- [Qemu-devel] [PATCH v4 25/26] tcg: Check for overflow via highwater mark, Richard Henderson, 2015/10/08
- Re: [Qemu-devel] [PATCH v4 25/26] tcg: Check for overflow via highwater mark,
Aurelien Jarno <=
- [Qemu-devel] [PATCH v4 10/26] target-sh4: Add flags state to insn_start, Richard Henderson, 2015/10/08
- [Qemu-devel] [PATCH v4 12/26] target-sparc: Tidy gen_branch_a interface, Richard Henderson, 2015/10/08
- [Qemu-devel] [PATCH v4 23/26] tcg: Emit prologue to the beginning of code_gen_buffer, Richard Henderson, 2015/10/08
- [Qemu-devel] [PATCH v4 02/26] target-*: Unconditionally emit tcg_gen_insn_start, Richard Henderson, 2015/10/08
- [Qemu-devel] [PATCH v4 04/26] target-*: Introduce and use cpu_breakpoint_test, Richard Henderson, 2015/10/08