Following up on the previous mail with patches for doing multiblock raw I/O
:
Experiments on a 2-way, 850MHz PIII, 256K cache, 256M memory
Running bonnie (modified to allow specification of O_DIRECT option,
target file etc.)
Only the block tests (rewrite,read,write) have been run. All tests
are single threaded.
BW = bandwidth in kB/s
cpu = %CPU use
abs = size of each I/O request
(NOT blocksize used by underlying raw I/O mechanism !)
pre2 = using kernel 2.4.13-pre2aa1
multi = 2.4.13-pre2aa1 kernel with multiblock raw I/O patches applied
(both /dev/raw and O_DIRECT)
/dev/raw (uses 512 byte blocks)
===============================
rewrite write read
------------------------------------------------------------------
pre2 multi pre2 multi pre2 multi
------------------------------------------------------------------
abs BW cpu BW cpu BW cpu BW cpu BW cpu BW cpu
------------------------------------------------------------------
4k 884 0.5 882 0.1 1609 0.3 1609 0.2 9841 1.5 9841 0.9
6k 884 0.5 882 0.2 1609 0.5 1609 0.1 9841 1.8 9841 1.2
16k 884 0.6 882 0.2 1609 0.3 1609 0.0 9841 2.7 9841 1.4
18k 884 0.4 882 0.2 1609 0.4 1607 0.1 9841 2.4 9829 1.2
64k 883 0.5 882 0.1 1609 0.4 1609 0.3 9841 2.0 9841 0.6
66k 883 0.5 882 0.2 1609 0.5 1609 0.2 9829 3.4 9829 1.0
O_DIRECT : on filesystem with 1K blocksize
===========================================
rewrite write read
------------------------------------------------------------------
pre2 multi pre2 multi pre2 multi
------------------------------------------------------------------
abs BW cpu BW cpu BW cpu BW cpu BW cpu BW cpu
------------------------------------------------------------------
4k 854 0.8 880 0.4 1527 0.5 1607 0.1 9731 2.5 9780 1.3
6k 856 0.4 882 0.3 1527 0.4 1607 0.1 9732 1.6 9780 0.7
16k 857 0.4 881 0.1 1527 0.3 1608 0.0 9732 2.2 9780 1.2
18k 857 0.3 882 0.2 1527 0.4 1607 0.1 9731 1.9 9780 1.0
64k 857 0.3 881 0.1 1526 0.4 1607 0.2 9732 1.6 9780 1.6
66k 856 0.4 882 0.2 1527 0.4 1607 0.2 9731 2.7 9780 1.2
Shailabh Nagar
Enterprise Linux Group, IBM TJ Watson Research Center
(914) 945 2851, T/L 862 2851
Hi!
We had 200MB/s on 2.2.18 with the SGI raw patch and CPU-Load
approximately 10%.
On 2.4.3-12, we get 100MB/s with 100% CPU-Load. Is there a way of
getting even bigger transfers than one page for the aligned part? With
the SGI patch, there was much less waiting for I/O completion because
we could transfer 1MB in one chunk. I'm sorry but I don't have time at
the moment to test the patch but I will send you our numbers as soon as
we have some time.
Good to see somebody working on it! Thanks!
Reto
Shailabh Nagar wrote:
>
> Following up on the previous mail with patches for doing multiblock raw I/O
> :
>
> Experiments on a 2-way, 850MHz PIII, 256K cache, 256M memory
> Running bonnie (modified to allow specification of O_DIRECT option,
> target file etc.)
> Only the block tests (rewrite,read,write) have been run. All tests
> are single threaded.
>
> BW = bandwidth in kB/s
> cpu = %CPU use
> abs = size of each I/O request
> (NOT blocksize used by underlying raw I/O mechanism !)
>
> pre2 = using kernel 2.4.13-pre2aa1
> multi = 2.4.13-pre2aa1 kernel with multiblock raw I/O patches applied
> (both /dev/raw and O_DIRECT)
>
> /dev/raw (uses 512 byte blocks)
> ===============================
>
> rewrite write read
> ------------------------------------------------------------------
> pre2 multi pre2 multi pre2 multi
> ------------------------------------------------------------------
> abs BW cpu BW cpu BW cpu BW cpu BW cpu BW cpu
> ------------------------------------------------------------------
> 4k 884 0.5 882 0.1 1609 0.3 1609 0.2 9841 1.5 9841 0.9
> 6k 884 0.5 882 0.2 1609 0.5 1609 0.1 9841 1.8 9841 1.2
> 16k 884 0.6 882 0.2 1609 0.3 1609 0.0 9841 2.7 9841 1.4
> 18k 884 0.4 882 0.2 1609 0.4 1607 0.1 9841 2.4 9829 1.2
> 64k 883 0.5 882 0.1 1609 0.4 1609 0.3 9841 2.0 9841 0.6
> 66k 883 0.5 882 0.2 1609 0.5 1609 0.2 9829 3.4 9829 1.0
>
> O_DIRECT : on filesystem with 1K blocksize
> ===========================================
>
> rewrite write read
> ------------------------------------------------------------------
> pre2 multi pre2 multi pre2 multi
> ------------------------------------------------------------------
> abs BW cpu BW cpu BW cpu BW cpu BW cpu BW cpu
> ------------------------------------------------------------------
> 4k 854 0.8 880 0.4 1527 0.5 1607 0.1 9731 2.5 9780 1.3
> 6k 856 0.4 882 0.3 1527 0.4 1607 0.1 9732 1.6 9780 0.7
> 16k 857 0.4 881 0.1 1527 0.3 1608 0.0 9732 2.2 9780 1.2
> 18k 857 0.3 882 0.2 1527 0.4 1607 0.1 9731 1.9 9780 1.0
> 64k 857 0.3 881 0.1 1526 0.4 1607 0.2 9732 1.6 9780 1.6
> 66k 856 0.4 882 0.2 1527 0.4 1607 0.2 9731 2.7 9780 1.2
>
> Shailabh Nagar
> Enterprise Linux Group, IBM TJ Watson Research Center
> (914) 945 2851, T/L 862 2851
>
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