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Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread f
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool |
Date: |
Fri, 28 Nov 2014 13:21:18 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 |
On 28/11/2014 12:32, Peter Lieven wrote:
> Am 28.11.2014 um 12:23 schrieb Paolo Bonzini:
>>
>> On 28/11/2014 12:21, Peter Lieven wrote:
>>> Am 28.11.2014 um 12:14 schrieb Paolo Bonzini:
>>>>> master:
>>>>> Run operation 40000000 iterations 12.851414 s, 3112K operations/s, 321ns
>>>>> per coroutine
>>>>>
>>>>> paolo:
>>>>> Run operation 40000000 iterations 11.951720 s, 3346K operations/s, 298ns
>>>>> per coroutine
>>>> Nice. :)
>>>>
>>>> Can you please try "coroutine: Use __thread … " together, too? I still
>>>> see 11% time spent in pthread_getspecific, and I get ~10% more indeed if
>>>> I apply it here (my times are 191/160/145).
>>> indeed:
>>>
>>> Run operation 40000000 iterations 10.138684 s, 3945K operations/s, 253ns
>>> per coroutine
>> Your perf_master2 uses the ring buffer unconditionally, right? I wonder
>> if we can use a similar algorithm but with arrays instead of lists...
>
> Why do you set pool_size = 0 in the create path?
>
> When I do the following:
> diff --git a/qemu-coroutine.c b/qemu-coroutine.c
> index 6bee354..c79ee78 100644
> --- a/qemu-coroutine.c
> +++ b/qemu-coroutine.c
> @@ -44,7 +44,7 @@ Coroutine *qemu_coroutine_create(CoroutineEntry *entry)
> * and the actual size of alloc_pool. But it is just a
> heuristic,
> * it does not need to be perfect.
> */
> - pool_size = 0;
> + atomic_dec(&pool_size);
> QSLIST_MOVE_ATOMIC(&alloc_pool, &release_pool);
> co = QSLIST_FIRST(&alloc_pool);
>
>
> I get:
> Run operation 40000000 iterations 9.883958 s, 4046K operations/s, 247ns per
> coroutine
Because pool_size is the (approximate) number of coroutines in the pool.
It is zero after QSLIST_MOVE_ATOMIC has NULL-ed out release_pool.slh_first.
Paolo
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, (continued)
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Peter Lieven, 2014/11/28
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Peter Lieven, 2014/11/28
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Peter Lieven, 2014/11/28
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Paolo Bonzini, 2014/11/28
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Peter Lieven, 2014/11/28
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Paolo Bonzini, 2014/11/28
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Peter Lieven, 2014/11/28
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Paolo Bonzini, 2014/11/28
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Peter Lieven, 2014/11/28
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Peter Lieven, 2014/11/28
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool,
Paolo Bonzini <=
- Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Peter Lieven, 2014/11/28
Re: [Qemu-devel] [RFC PATCH 3/3] qemu-coroutine: use a ring per thread for the pool, Stefan Hajnoczi, 2014/11/28
[Qemu-devel] [RFC PATCH 1/3] Revert "coroutine: make pool size dynamic", Peter Lieven, 2014/11/27