Re: Question about IoCtx::aio_exec semantics

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Fantastic. Thanks!

-Noah

On Apr 19, 2012, at 12:34 PM, Yehuda Sadeh Weinraub wrote:

> On Thu, Apr 19, 2012 at 12:04 PM, Noah Watkins <jayhawk@xxxxxxxxxxx> wrote:
>> I've had a lot of success using rados_exec(), but I need to graduate the implementation to use IoCtx::aio_exec for increased concurrency. I'm a little confused about how aio_exec should be used:
>> 
>> Here is aio_exec:
>> 
>>   int aio_exec(const std::string& oid, AioCompletion *c, const char *cls, const char *method, bufferlist& inbl, bufferlist *outbl);
>> 
>> I'd like to have many outstanding competitions, one for each call of aio_exec. Once @c has completed, I'd like to have access to the @outbl bufferlist. So, is the intended use here to allocate an empty bufferlist for each submitted completion?
> 
> Yes, you'll need to have a bufferlist for each request sent if your
> exec is expected to return data. Note that only read operations should
> return data.
>> 
>> In rgw/rgw_rados.cc a use is:
>> 
>>  AioCompletion *c = librados::Rados::aio_create_completion(NULL, NULL, NULL);
>>  r = io_ctx.aio_exec(oid, c, "rgw", "dir_suggest_changes", in, NULL);
>>  c->release();
>> 
>> To clarify, are the semantics here that an asynchronous aio_exec is made without checking for completion or return values.
> 
> Right. We send the "dir_suggest_changes" request and dropping the
> reference, so that we can't get the return value once it's done.
> 
> Yehuda

--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [CEPH Users]     [Ceph Large]     [Information on CEPH]     [Linux BTRFS]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]
  Powered by Linux