Re: [Qemu-devel] [PATCH v2 4/4] coroutine: pool coroutines to speed up creation

[Stefan Hajnoczi <stefanha@gmail.com>]

On Thu, May 12, 2011 at 11:13 AM, Kevin Wolf <kwolf@redhat.com> wrote:
> terAm 12.05.2011 11:54, schrieb Stefan Hajnoczi:
>> This patch speeds up coroutine creation by reusing freed coroutines.
>> When a coroutine terminates it is placed in the pool instead of having
>> its resources freed.  The next time a coroutine is created it can be
>> taken straight from the pool and requires no initialization.
>>
>> Performance results on an Intel Core2 Duo T9400 (2.53GHz) for
>> ./check-coroutine --benchmark-lifecycle 20000000:
>>
>>   No pooling:    19.5 sec
>>   With pooling:   1.1 sec
>>
>> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
>> ---
>>  check-coroutine.c    |    2 ++
>>  qemu-coroutine-int.h |    2 ++
>>  qemu-coroutine.c     |   49 ++++++++++++++++++++++++++++++++++++++++++++++---
>>  qemu-coroutine.h     |    9 +++++++++
>>  vl.c                 |    2 ++
>>  5 files changed, 61 insertions(+), 3 deletions(-)
>>
>> diff --git a/check-coroutine.c b/check-coroutine.c
>> index 5a42c49..223c50c 100644
>> --- a/check-coroutine.c
>> +++ b/check-coroutine.c
>> @@ -218,6 +218,8 @@ int main(int argc, char **argv)
>>      };
>>      int i;
>>
>> +    qemu_coroutine_init();
>
> Can we use module_init instead of adding an explicit call to main()?
> This would prevent forgetting to add it in qemu-img and qemu-io like in
> this patch.

module_init what? :)  qemu-img/qemu-io only init MODULE_INIT_BLOCK so
we'd have to modify them anyway.

I don't want to add qemu-img/qemu-io things yet because we don't have
a block layer user for coroutines yet.  The qcow2 patches should
contain these changes.

Stefan