Re: using fio client on 64-bit machine with fio server on 32-bit machine

[Jens Axboe <axboe@kernel.dk>]

On 06/27/2014 10:47 AM, Jens Axboe wrote:
> On 2014-06-27 01:00, Frank D'Arcy wrote:
>> Hi,
>> I've been playing around with fio (which is really great thanks)
>> with a view to testing hard disks on set-top boxes (which I don't have
>> yet)
>> and as prep for this I created a test environment consisting of
>> 2 x virtual machines running 32-bit ubuntu (using "hashicorp/precise32"
>> from vagrant cloud)
>> running on a 64-bit machine with ubuntu 12.04.
>>
>> I started fio (v2.1.10) running in server mode on both virtual machines
>> as follows
>> $ fio --server=,8880
>>
>> and launched 2 fio (v2.1.10) instances in client mode on the host 64-bit
>> machine,
>> $ fio --client=ip:127.0.0.1,8882 test.fio
>> $ fio --client=ip:127.0.0.1,8881 test.fio
>> where ports 8881 and 8882 are forwarded to port 8880 on each VM
>>
>> The sample test.fio (below) runs for 25 seconds
>> but the values printed by the clients look garbled.
>> eg. runtime is a huge number ("runt= 107374182400000msec")
>>
>> Same issue is seen when I switched to using latest fio from "git clone"
>> and the same issue is seen with all output formats (json, terse, normal)
>>
>> I changed one of the virtual machines to 64-bit ubuntu (using
>> "hashicorp/precise64" from vagrant cloud)
>> and the client talking to the fio server on that VM gave the correct
>> results (eg. "runt= 25001msec")
>> while the client talking to the 32-bit ubuntu VM continued to show
>> garbled values.
>>
>> So it looks like support is not there for client-server setups on
>> non-matching architectures ?
>> eg. 32-bit client to 64-bit server in this case,
>> and perhaps endianess differences would be a problem too? ( but I
>> haven't tried that )
>>
>> Apologies if I've missed this issue raised elsewhere, I did a quick
>> search and found no mention of it.
>> It's not critical for us, as the simple workaround is to run fio
>> standalone on each set-top box
>> outputting results to a file and pulling the file back to a central
>> machine for parsing.
>> Just wanted to raise it if its unknown to you.
> 
> Any mix of 32 vs 64-bit and big vs little endian should work, all the
> data structures are sanitized across the wire. So if it doesn't work,
> then that is surely a bug! I'll take a look at this.

http://git.kernel.dk/?p=fio.git;a=commit;h=819db5f5009742975cfdd036440522bd45b86fe7

this should make it behave better. Let me know if there are still issues
with 32 vs 64 bit client/server.

-- 
Jens Axboe