opening a big book = very high cpu ?

[cybmole]

I am curious as to why opening any very big book in sigil such as an omnibus edition - anything with 1500+ pages, will interfere with cause my CPU fan to kick in - indicating v high cpu usage. I can't think of any other non-gaming application that causes that, not even a DVD rip or video conversion - so what is going on within sigil that needs such CPU power ?

CPU fan will go on + my mouse movement becomes erratic, then just as I'm thinking "we're gonna crash any second", the sigil window will appear & we are back to normal...

I am using a fast dual core cpu so sigil must be temporarily monopolising both cores ?

could it be a side effect of the tidy - check/clean book when opening setting ?

[cybmole]

update on this & testing with clean on open set to OFF.

for a 2700 page omnibus - open with sigil is about 30 seconds. but open same book with the new calibre book editor is about 4 seconds - is that solely due to use of python in place of C++ ?

( am using 64 bit calibre- but should that make any difference to "open book" speed ? )

[mrmikel]

Seems like I remember reading that Kovid said that he does as little as possible compared to Sigil. The whole book is checked on open always in Sigil or laid out in Sigil format or something. I'll check over in the new forum and see if I can find it.

..found it:

That's how the new database backend is faster than the old, despite actually being thread safe, which involves overhead for locking. And it's why the editor is so fast. By using various, rather nifty tricks, I was able to make the editor fast. The basic idea is to do as little as possible and that, only when absolutely necessary.

For example, Sigil parses all files when the book is first opened and renames them. There's absolutely no need to do that. Instead, calibre works with html even if it is not strictly valid.

Another trick is that the parsing and fixing of html before displaying in the preview panel happens in a separate process, so it keeps the editor itself feeling responsive, while the heavy works happens on a different CPU core.

[cybmole]

Thanks for tracking down the reference- it must be that initial parsing that hammers the CPU then, its only really noticeable on very large books but once you get into multi volume omnibus territory....
lets try the biggest fish in my pond: game of thrones 5 book bundle 4,700+ lines - calibre editor ~9 secs, sigil ...still wating.....

....

- I can hear the CPU fan....

...

...no sign of the book yet...

eventually I stopped counting but I reckon 3+ minutes before sigil was ready to use

[Katsunami]

Sgil is slow, because it completely rearranges the book into a new directory structure and update the book accordingly. If set, it'll also clean and reformat the HTML on opening. It does require a lot of CPU power, and it can take several *minutes* to open large books (as you have already observed).

Edit Book just explodes the book and shows the files, without rearranging or cleaning anythig (as long as you don't tell it to do so), so it's much faster opening large books.