Re: measuring swap partition speed

On Sat, Dec 23, 2023 at 11:55:43AM -0800, Mark Millard wrote:

>If you had the resources to test avoiding the encrypted
>partition for your type of media, that might prove
>interesting.

The problem remains even with UFS. It remains after any non-swap i/o
load stops, even when swap is not otherwise in use. 

I took /dev/da0p5, formatted it with newfs -U and put it at /mnt.

then

root@pi4:/mnt# date && git clone https://git.freebsd.org/ports.git
Sun Dec 24 12:06:50 GMT 2023
Cloning into 'ports'...
remote: Enumerating objects: 6044522, done.
remote: Counting objects: 100% (941/941), done.
remote: Compressing objects: 100% (125/125), done.
remote: Total 6044522 (delta 923), reused 821 (delta 816), pack-reused 6043581
Receiving objects: 100% (6044522/6044522), 1.16 GiB | 6.94 MiB/s, done.
^Csolving deltas:   2% (101172/3649394)

date && dd if=/dev/urandom of=/dev/da0p6 bs=8k conv=sync status=progress
Sun Dec 24 12:06:52 GMT 2023
^C203841536 bytes (204 MB, 194 MiB) transferred 205.012s, 994 kB/s 
25009+0 records in
25008+0 records out
204865536 bytes transferred in 205.914885 secs (994904 bytes/sec)

cancelled both processes, checked swap

# date && swapinfo -h
Sun Dec 24 12:11:56 GMT 2023
Device              Size     Used    Avail Capacity
/dev/da0p2          2.0G       0B     2.0G     0%
/dev/da0p4          2.0G       0B     2.0G     0%
/dev/da0p6          2.0G       0B     2.0G     0%
/dev/da0p8          2.0G       0B     2.0G     0%
Total               8.0G       0B     8.0G     0%

while /dev/da0p6 is available as swap to the system

# date && dd if=/dev/urandom of=/dev/da0p6 bs=8k conv=sync status=progress
Sun Dec 24 12:10:38 GMT 2023
^C78790656 bytes (79 MB, 75 MiB) transferred 96.008s, 821 kB/s   
9767+0 records in
9766+0 records out
80003072 bytes transferred in 96.986518 secs (824889 bytes/sec)

# swapoff /dev/da0p6

# date && dd if=/dev/urandom of=/dev/da0p6 bs=8k conv=sync status=progress
Sun Dec 24 12:21:28 GMT 2023
dd: /dev/da0p6: end of device2031 MiB) transferred 105.007s, 20 MB/s

262145+0 records in
262144+0 records out
2147483648 bytes transferred in 105.837991 secs (20290291 bytes/sec)
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