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Re: [Qemu-devel] [PATCH v2 0/6] Reduce lock contention on TCG hot-path
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/6] Reduce lock contention on TCG hot-path |
Date: |
Thu, 07 Jul 2016 20:38:43 +0100 |
User-agent: |
mu4e 0.9.17; emacs 25.0.95.7 |
Emilio G. Cota <address@hidden> writes:
> On Tue, Jul 05, 2016 at 17:18:10 +0100, Alex Bennée wrote:
>> Well this is the first re-spin of the series posted last week. I've
>> added a bunch of additional patches to be more aggressive with
>> avoiding bouncing locks but to be honest the numbers don't seem to
>> make it worth it.
>
> How many threads are you using? With just a few threads I wouldn't
> expect a measurable difference.
My setup is 8 "cores" which pigz expands to use but I know you have
beefier machines on hand ;-)
>
>> I think the first 3 patches are ready to take if the TCG maintainers
>> want to:
>>
>> tcg: Ensure safe tb_jmp_cache lookup out of 'tb_lock'
>> tcg: set up tb->page_addr before insertion
>> tcg: cpu-exec: remove tb_lock from the hot-path
>
> I think it would be simpler to use tb_lock_recursive and
> tb_lock_reset, as pointed out in v1 of this series.
I didn't realise people were suggesting asymmetric lock taking/reseting.
It seems ugly IMHO.
>
> Thanks,
>
> Emilio
--
Alex Bennée
- [Qemu-devel] [PATCH 2/3] tcg: Introduce tb_lock_locked(), (continued)
- [Qemu-devel] [PATCH 2/3] tcg: Introduce tb_lock_locked(), Sergey Fedorov, 2016/07/07
- [Qemu-devel] [PATCH 1/3] tcg: Introduce mmap_lock_reset(), Sergey Fedorov, 2016/07/07
- [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Sergey Fedorov, 2016/07/07
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Alex Bennée, 2016/07/07
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Sergey Fedorov, 2016/07/07
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Sergey Fedorov, 2016/07/07
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Alex Bennée, 2016/07/07
Re: [Qemu-devel] [PATCH v2 0/6] Reduce lock contention on TCG hot-path, Emilio G. Cota, 2016/07/07