* [patch 8/9] fio: fix last block never being touched by random offsets
@ 2014-02-20 13:20 ehrhardt
2014-02-20 17:18 ` Jens Axboe
0 siblings, 1 reply; 5+ messages in thread
From: ehrhardt @ 2014-02-20 13:20 UTC (permalink / raw)
To: fio; +Cc: oberpar, Christian Ehrhardt
*Resend with hopefully non mangled patches*
References: <20140220131958.965092001@linux.vnet.ibm.com>
Content-Disposition: inline; filename=fix_last_block.diff
From: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Fix the available range for random offsets which never touched the last block.
Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
---
[diffstat]
io_u.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/io_u.c
+++ b/io_u.c
@@ -104,7 +104,7 @@ static int __get_next_rand_offset(struct
dprint(FD_RANDOM, "off rand %llu\n", (unsigned long long) r);
- *b = (lastb - 1) * (r / ((uint64_t) rmax + 1.0));
+ *b = lastb * (r / ((uint64_t) rmax + 1.0));
} else {
uint64_t off = 0;
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [patch 8/9] fio: fix last block never being touched by random offsets
2014-02-20 13:20 [patch 8/9] fio: fix last block never being touched by random offsets ehrhardt
@ 2014-02-20 17:18 ` Jens Axboe
2014-02-28 16:46 ` Peter Oberparleiter
0 siblings, 1 reply; 5+ messages in thread
From: Jens Axboe @ 2014-02-20 17:18 UTC (permalink / raw)
To: ehrhardt; +Cc: fio, oberpar
On Thu, Feb 20 2014, ehrhardt@linux.vnet.ibm.com wrote:
> *Resend with hopefully non mangled patches*
> References: <20140220131958.965092001@linux.vnet.ibm.com>
> Content-Disposition: inline; filename=fix_last_block.diff
>
> From: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
>
> Fix the available range for random offsets which never touched the last block.
>
> Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
> ---
> [diffstat]
> io_u.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/io_u.c
> +++ b/io_u.c
> @@ -104,7 +104,7 @@ static int __get_next_rand_offset(struct
>
> dprint(FD_RANDOM, "off rand %llu\n", (unsigned long long) r);
>
> - *b = (lastb - 1) * (r / ((uint64_t) rmax + 1.0));
> + *b = lastb * (r / ((uint64_t) rmax + 1.0));
> } else {
> uint64_t off = 0;
Wont this generate lastb as the potentially last block? We want lastb-1
as the last one, otherwise the length of IO from it will be 0.
I might be missing something here.
--
Jens Axboe
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [patch 8/9] fio: fix last block never being touched by random offsets
2014-02-20 17:18 ` Jens Axboe
@ 2014-02-28 16:46 ` Peter Oberparleiter
2014-02-28 17:07 ` Jens Axboe
0 siblings, 1 reply; 5+ messages in thread
From: Peter Oberparleiter @ 2014-02-28 16:46 UTC (permalink / raw)
To: Jens Axboe, ehrhardt; +Cc: fio
On 20.02.2014 18:18, Jens Axboe wrote:
> On Thu, Feb 20 2014, ehrhardt@linux.vnet.ibm.com wrote:
>> *Resend with hopefully non mangled patches*
>> References: <20140220131958.965092001@linux.vnet.ibm.com>
>> Content-Disposition: inline; filename=fix_last_block.diff
>>
>> From: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
>>
>> Fix the available range for random offsets which never touched the last block.
>>
>> Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
>> ---
>> [diffstat]
>> io_u.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> --- a/io_u.c
>> +++ b/io_u.c
>> @@ -104,7 +104,7 @@ static int __get_next_rand_offset(struct
>>
>> dprint(FD_RANDOM, "off rand %llu\n", (unsigned long long) r);
>>
>> - *b = (lastb - 1) * (r / ((uint64_t) rmax + 1.0));
>> + *b = lastb * (r / ((uint64_t) rmax + 1.0));
>> } else {
>> uint64_t off = 0;
>
> Wont this generate lastb as the potentially last block? We want lastb-1
> as the last one, otherwise the length of IO from it will be 0.
>
> I might be missing something here.
I would expect that the last I/O would be at offset size-blocksize and
size blocksize. Consider this example test case that should generate 1
second of random reads with offsets 0 and 512:
[job]
filename=datafile
blocksize=512
size=1024
time_based
runtime=1
rw=randread
norandommap
write_iolog=/dev/stdout
Running it with FIO_VERSION = fio-2.1.5-44-ga1fc produces the following
result:
> fio job | grep datafile | sort | uniq
datafile add
datafile close
datafile open
datafile read 0 512
-> I/O is only generated for offset 0
Running it with the same version and the subject patch applied:
> fio job | grep datafile | sort | uniq
datafile add
datafile close
datafile open
datafile read 0 512
datafile read 512 512
-> Both offsets are covered
--
Peter Oberparleiter
Linux on System z Development - IBM Germany
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [patch 8/9] fio: fix last block never being touched by random offsets
2014-02-28 16:46 ` Peter Oberparleiter
@ 2014-02-28 17:07 ` Jens Axboe
0 siblings, 0 replies; 5+ messages in thread
From: Jens Axboe @ 2014-02-28 17:07 UTC (permalink / raw)
To: Peter Oberparleiter, ehrhardt; +Cc: fio
On 2014-02-28 08:46, Peter Oberparleiter wrote:
> On 20.02.2014 18:18, Jens Axboe wrote:
>> On Thu, Feb 20 2014, ehrhardt@linux.vnet.ibm.com wrote:
>>> *Resend with hopefully non mangled patches*
>>> References: <20140220131958.965092001@linux.vnet.ibm.com>
>>> Content-Disposition: inline; filename=fix_last_block.diff
>>>
>>> From: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
>>>
>>> Fix the available range for random offsets which never touched the last block.
>>>
>>> Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
>>> ---
>>> [diffstat]
>>> io_u.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> --- a/io_u.c
>>> +++ b/io_u.c
>>> @@ -104,7 +104,7 @@ static int __get_next_rand_offset(struct
>>>
>>> dprint(FD_RANDOM, "off rand %llu\n", (unsigned long long) r);
>>>
>>> - *b = (lastb - 1) * (r / ((uint64_t) rmax + 1.0));
>>> + *b = lastb * (r / ((uint64_t) rmax + 1.0));
>>> } else {
>>> uint64_t off = 0;
>>
>> Wont this generate lastb as the potentially last block? We want lastb-1
>> as the last one, otherwise the length of IO from it will be 0.
>>
>> I might be missing something here.
>
> I would expect that the last I/O would be at offset size-blocksize and
> size blocksize. Consider this example test case that should generate 1
> second of random reads with offsets 0 and 512:
>
> [job]
> filename=datafile
> blocksize=512
> size=1024
> time_based
> runtime=1
> rw=randread
> norandommap
> write_iolog=/dev/stdout
>
> Running it with FIO_VERSION = fio-2.1.5-44-ga1fc produces the following
> result:
>
>> fio job | grep datafile | sort | uniq
> datafile add
> datafile close
> datafile open
> datafile read 0 512
>
> -> I/O is only generated for offset 0
>
> Running it with the same version and the subject patch applied:
>
>> fio job | grep datafile | sort | uniq
> datafile add
> datafile close
> datafile open
> datafile read 0 512
> datafile read 512 512
>
> -> Both offsets are covered
Tested here, and it does look correct. Thanks, I will apply it.
--
Jens Axboe
^ permalink raw reply [flat|nested] 5+ messages in thread
* [patch 8/9] fio: fix last block never being touched by random offsets
[not found] <20140219143639.168501090@linux.vnet.ibm.com>
@ 2014-02-19 15:12 ` Christian Ehrhardt
0 siblings, 0 replies; 5+ messages in thread
From: Christian Ehrhardt @ 2014-02-19 15:12 UTC (permalink / raw)
To: fio; +Cc: oberpar, Christian Ehrhardt
From: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Fix the available range for random offsets which never touched the last
block.
Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
---
[diffstat]
io_u.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/io_u.c
+++ b/io_u.c
@@ -104,7 +104,7 @@ static int __get_next_rand_offset(struct
dprint(FD_RANDOM, "off rand %llu\n", (unsigned long long) r);
- *b = (lastb - 1) * (r / ((uint64_t) rmax + 1.0));
+ *b = lastb * (r / ((uint64_t) rmax + 1.0));
} else {
uint64_t off = 0;
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2014-02-28 17:07 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-02-20 13:20 [patch 8/9] fio: fix last block never being touched by random offsets ehrhardt
2014-02-20 17:18 ` Jens Axboe
2014-02-28 16:46 ` Peter Oberparleiter
2014-02-28 17:07 ` Jens Axboe
[not found] <20140219143639.168501090@linux.vnet.ibm.com>
2014-02-19 15:12 ` Christian Ehrhardt
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