Are you using the OfflineIMAP SQLite driver? If not, the maintainers did say it was more performant and reliable than using text files which was the default before version 7.
Yes, I use the SQLite driver, and use & regularly pull the latest version from the git, 7.1 right now.
I haven't dug into why it uses that CPU in any detail. Looking at its output / tcpdump of what it's doing it goes to >100% CPU for 10-30 seconds when it's finished fetching the status from the remote & is presumably in some tight inner loop comparing it with local data to decide what to do before it starts downloading messages, and then briefly spends a few more seconds at >100% after the messages are downloaded, presumably updating its local state.
When it's just issuing IMAP commands or downloading messages from the remote it sits at 1-5% CPU.
As I pointed out OfflineIMAP works just fine for me, but in retrospect I'd be happier if I had stayed with mbsync. I don't need any feature from OfflineIMAP that it doesn't have, and it both uses less CPU/Memory & it finishes deciding what to download & downloading it in way less time.
I have just checked how much it uses on my side: doesn't go above 50%, but I do consider that pretty high and can totally understand how it could use 100% with bigger mailboxes. For me, this was never a problem since I only run it once daily for backup.
Thank you for mentioning mbsync, I will keep it in mind.
I haven't dug into why it uses that CPU in any detail. Looking at its output / tcpdump of what it's doing it goes to >100% CPU for 10-30 seconds when it's finished fetching the status from the remote & is presumably in some tight inner loop comparing it with local data to decide what to do before it starts downloading messages, and then briefly spends a few more seconds at >100% after the messages are downloaded, presumably updating its local state.
When it's just issuing IMAP commands or downloading messages from the remote it sits at 1-5% CPU.
As I pointed out OfflineIMAP works just fine for me, but in retrospect I'd be happier if I had stayed with mbsync. I don't need any feature from OfflineIMAP that it doesn't have, and it both uses less CPU/Memory & it finishes deciding what to download & downloading it in way less time.