| Summary: | High CPU usage on reading specific file | ||
|---|---|---|---|
| Product: | poppler | Reporter: | Alexander Hunziker <alex.hunziker> |
| Component: | utils | Assignee: | poppler-bugs <poppler-bugs> |
| Status: | RESOLVED MOVED | QA Contact: | |
| Severity: | normal | ||
| Priority: | medium | CC: | L.Bonnaud, mr |
| Version: | unspecified | ||
| Hardware: | All | ||
| OS: | All | ||
| Whiteboard: | |||
| i915 platform: | i915 features: | ||
| Attachments: | the file | ||
|
Description
Alexander Hunziker
2012-09-10 19:04:12 UTC
Assigning to cairo backend, splash takes 74ms, cairo takes 14s The file cannot be downloaded any longer. Could someone please upload it again? Created attachment 115413 [details]
the file
Thanks! I confirm that this bug still exists in poppler 0.30.0 in Ubuntu 15.04. Viewing this file takes a very long time, both in evince and okular. Even pdftotext takes ages to convert it (into a useless text file) and indexing it with baloo or tracker also uses too much CPU. Other data points: - xpdf also uses a lot of CPU to display the file - gv, which uses GhostScript, and gs itself can display the file instantly The problem is here neither the splash backend nor the cairo backend. Rendering the PDF is fast with splash and with cairo. The problem is the TextOutputDev used in okular and in evince to make the text searchable. TextOutputDev tries to sort the text into readind order by performing a topological, and this is really slow for this document. And is even not necessary: because all fonts are embedded and all use a custom encoding the content will never be searchable. But I'm not an expert in TextOutputDev, I just figured out that pdftotext -raw is much faster, so evince and okular perhaps can detect that the text will not be readable and omit the text extracting? Good catch! Here are time measurements on my system: $ time pdftotext bug-poppler54746.pdf real 5m52.502s user 5m52.884s sys 0m0.016s $ time pdftotext -raw bug-poppler54746.pdf real 0m0.280s user 0m0.244s sys 0m0.020s There are perhaps bugs in evince and okular (I will report them), but a similar bug exists in pdftotext and should be fixed... I think one thing to do is to run the textoutputdev and the splash/cairo output dev in paralell and if the textouputdev takes too long, then just abort this part and emit a sort of error. This sounds like something to do on Evince and Okular, but just stating the idea here. Evince is not thread-safe (we queue calls to Poppler), so making this work in evince will take more efforts. I don't know about Okular. The actual problem is that textouputdev sorting code is veeeeery slow, that's why raw vs nonraw is so different -- GitLab Migration Automatic Message -- This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity. You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/poppler/poppler/issues/254. |
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