mutt seems laggy to resume on v.2.x

[Cameron Simpson]

On 25Nov2020 14:19, tech-lists <tech-lists at zyxst.net> wrote:
>I'm finding mutt significantly more laggy to resume on later
>versions (=>2.x) than say 1.5.21.
>
>Let's say there's the list of emails in a folder already selected. If 
>I use up or down arrow for example, it'll sit for 3-4 seconds doing 
>nothing and then move. But once moving, it's
>as responsive as it's always been before.
>
>Then, say 5 minutes happen where nothing happens. Slow to move
>around again. I'm using imaps. It's not having to re-authenticate, so 
>the connection isn't dropping. Ping times to the imap server are 77ms, 
>no packet loss.
[...]
>For context:
>freebsd-current (all debugging has been turned off)
>TMP is ~/tmp and is tmpfs (memory) mounted.
>$HOME is usb3-mounted spinning rust.

I don't know why version 2.x would be worse than 1.5.21 off hand. But...

USB3-mounted spinning rust has a strong tendency to spin down when idle, 
it is usually also a physically slow variety of drive (if USB-powered - 
low power consumption).

Do you use the header cache? That would involve local disc access to 
resume activity (looking up headers to present in the index, etc).

A way to check this would be to have another window open running:

    strace -p pid-of-idle-mutt-process

Get that ready. Wait for idleness. Resume. See where it stalls.

If that is hard to observe interactively, strace has options for 
including timestamps in the trace output, you could do the resume and 
then scroll back looking for the stall in the timestamps.

Cheers,
Cameron Simpson <cs at cskk.id.au>