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Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump() |
Date: |
Fri, 8 Jul 2016 22:52:11 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
On 08/07/2016 22:24, Sergey Fedorov wrote:
> I remember, I've just found that we discussed it in this thread:
>
> http://thread.gmane.org/gmane.comp.emulators.qemu/401723/focus=406852
>
> I was thinking of just doing 'tb_jmp_cache' lookup out of the lock, not
> tb_find_physical(). Now thanks to QHT, we could do tb_find_physical()
> out of the lock, too. This changes things.
But in my patch ("tcg: move tb_find_fast outside the tb_lock critical
section", which originally was written by Fred---most of my contribution
was getting the invalidation right, not the lock-free lookup)
tb_find_physical was also done out of the lock. It was then retried
inside the lock, if it failed.
This is why I needed to fail all concurrent lookups as the first step in
the invalidation.
Emilio's QHT resulted in a rewrite of tb_find_physical, but the basic
concepts are the same.
Paolo
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), (continued)
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Paolo Bonzini, 2016/07/08
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Sergey Fedorov, 2016/07/08
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Paolo Bonzini, 2016/07/08
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Sergey Fedorov, 2016/07/08
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Paolo Bonzini, 2016/07/08
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Sergey Fedorov, 2016/07/08
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Paolo Bonzini, 2016/07/08
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Sergey Fedorov, 2016/07/08
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(),
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Sergey Fedorov, 2016/07/11
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Paolo Bonzini, 2016/07/11
- Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Sergey Fedorov, 2016/07/11
Re: [Qemu-devel] [PATCH v2 0/6] Reduce lock contention on TCG hot-path, Emilio G. Cota, 2016/07/07