From: Surbhi Palande <csurbhi@gmail.com>
To: fio@vger.kernel.org
Subject: Requesting help with random I/O distribution
Date: Thu, 8 Jun 2023 18:11:54 -0700 [thread overview]
Message-ID: <CAMBkX3dN8d5kSNUDpPBBmx34+Ov7JzgK=dmgwAfeAaecLX+-7A@mail.gmail.com> (raw)
Hi All,
I am trying to performance test my device mapper for zoned devices; I
am trying to repliate the 80 - 20 principle for I/O. I understand that
this can be done in the following three ways using fio.
a) zoned - simplest of the three :
zoned:80/20:20/80
However, this restricts the first 20% space to get 80% of the I/O and
vice versa. The good thing though is that zoned distribution can be
used to achieve a russian doll effect.
b) zipf:1.2
I used fio-genzipf to visualize the random I/O pattern:
fio-genzipf -t zipf -i 1.2 -b 4096 -g 100GiB
Generating Zipf distribution with 1.200000 input and 100 GiB size and
4096 block_size.
Rows Hits % Sum % # Hits Size
-----------------------------------------------------------------------
Top 5.00% 93.31% 93.31% 24459924 93.31G
|-> 10.00% 1.34% 94.65% 352314 1.34G
|-> 15.00% 0.77% 95.42% 201010 785.20M
|-> 20.00% 0.51% 95.92% 132667 518.23M
|-> 25.00% 0.47% 96.39% 122386 478.07M
|-> 30.00% 0.34% 96.73% 89402 349.23M
|-> 35.00% 0.23% 96.97% 61193 239.04M
|-> 40.00% 0.23% 97.20% 61193 239.04M
|-> 45.00% 0.23% 97.43% 61193 239.04M
|-> 50.00% 0.23% 97.67% 61193 239.04M
|-> 55.00% 0.23% 97.90% 61193 239.04M
|-> 60.00% 0.23% 98.13% 61193 239.04M
|-> 65.00% 0.23% 98.37% 61193 239.04M
|-> 70.00% 0.23% 98.60% 61193 239.04M
|-> 75.00% 0.23% 98.83% 61193 239.04M
|-> 80.00% 0.23% 99.07% 61193 239.04M
|-> 85.00% 0.23% 99.30% 61193 239.04M
|-> 90.00% 0.23% 99.53% 61193 239.04M
|-> 95.00% 0.23% 99.77% 61193 239.04M
|-> 100.00% 0.23% 100.00% 61188 239.02M
-----------------------------------------------------------------------
Total 26214400
I need help with this interpretation. Does this mean that 5% of the
LBAs get 93.31% hits, the next 5% gets 1.34% etc. It seems that way to
me.
However, this does not have the Russian doll effect - ie the 5% of
the rest of 95% does not get the rest of ~93% I/O.
Is the 5% range - scattered over the disk or is this similar to zoned
distribution, in that a contiguous
space gets the 93% I/O. In that case, this is similar to zoned
distribution, right?
c) pareto -
fio-genzipf -t pareto -i 0.04 -b 4096 -g 100GiB
Generating Pareto distribution with 0.040000 input and 100 GiB size
and 4096 block_size.
Rows Hits % Sum % # Hits Size
-----------------------------------------------------------------------
Top 5.00% 93.04% 93.04% 24388831 93.04G
|-> 10.00% 0.99% 94.02% 259143 1012.28M
|-> 15.00% 0.60% 94.63% 158285 618.30M
|-> 20.00% 0.59% 95.22% 154826 604.79M
|-> 25.00% 0.35% 95.57% 92138 359.91M
|-> 30.00% 0.30% 95.87% 77413 302.39M
|-> 35.00% 0.30% 96.16% 77413 302.39M
|-> 40.00% 0.30% 96.46% 77413 302.39M
|-> 45.00% 0.30% 96.75% 77413 302.39M
|-> 50.00% 0.30% 97.05% 77413 302.39M
|-> 55.00% 0.30% 97.34% 77413 302.39M
|-> 60.00% 0.30% 97.64% 77413 302.39M
|-> 65.00% 0.30% 97.93% 77413 302.39M
|-> 70.00% 0.30% 98.23% 77413 302.39M
|-> 75.00% 0.30% 98.52% 77413 302.39M
|-> 80.00% 0.30% 98.82% 77413 302.39M
|-> 85.00% 0.30% 99.11% 77413 302.39M
|-> 90.00% 0.30% 99.41% 77413 302.39M
|-> 95.00% 0.30% 99.70% 77413 302.39M
|-> 100.00% 0.30% 100.00% 77395 302.32M
-----------------------------------------------------------------------
Total 26214400
This to me looks pretty much similar to the zipf distribution above.
Is this understanding correct ? Or am I missing something here?
Thanks a lot for your help!
next reply other threads:[~2023-06-09 1:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-09 1:11 Surbhi Palande [this message]
2023-06-16 20:28 ` Requesting help with random I/O distribution Vincent Fu
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