We've done some experiments with the onboard compression on our brand
new z15 and are implementing the compression in our products where it
makes sense. We have a CMS pipes stage written to make playing easy, so
have CMS functionality. As well as the assembler bits.
We also included the onboard compression in our z/OS Collector running
on z/OS, sending SMF records over to z/VM. Very unexpected results.
Getting about a 90% reduction in data transmission requirements, but
more amazing, we can measure a drop in overall cpu on z/OS by using the
compression. So we are compressing the data on z/os, and by doing so
are reducing the overall cpu requirements to transmit the SMF records.
On 6/9/2020 4:36 PM, Michael MacIsaac wrote:
Hello list,
I heard about the new DFLTCC instruction on the z15, aka on board
compression. I tried a quick experiment to see the difference from a z14.
Disclaimer: I am not a performance expert.
Here are three commands to create, compress and decompress a 1G file on a
z14:
# grep Type: /proc/sysinfo
Type: 3906
# time dd if=/dev/zero of=1G.file bs=1G count=1
1+0 records in
1+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 21.93 s, 49.0 MB/s
real 0m22.047s
user 0m0.001s
sys 0m3.669s
# time cat 1G.file | gzip -c > 1G.compressed.file
real 0m7.603s
user 0m5.362s
sys 0m0.789s
# time cat 1G.compressed.file | gzip -d > 1G.file
real 0m24.833s
user 0m4.103s
sys 0m1.845s
Here's the same commands on z15:
# grep Type: /proc/sysinfo
Type: 8561
# time dd if=/dev/zero of=1G.file bs=1G count=1
1+0 records in
1+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 1.59126 s, 675 MB/s
real 0m1.621s
user 0m0.000s
sys 0m1.216s
# time cat 1G.file | gzip -c > 1G.compressed.file
real 0m5.722s
user 0m4.946s
sys 0m0.510s
# time cat 1G.compressed.file | gzip -d > 1G.file
real 0m6.150s
user 0m3.922s
sys 0m1.290s
Wow more than 10x faster on dd - was not expecting that as I didn't think
it uses compression. But the compress with gzip -c, was only 25% faster on
the z15 while the decompress was about 4x.
Are these results expected?
Thanks.
--
-Mike MacIsaac
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