Use lazy imports to speed up sage startup time

[williamstein]

Sage still takes too long. 20 seconds, 30 seconds, 5 seconds, on various places... and it is all so painful. This patch attempts to speed up the startup time using lazy imports.

Specific patches at

• Lazily import schemes to save startuptime #11040 - sage.schemes
• Lazily import plot. #11043 - sage.plot

Component: misc

Keywords: sd32

Author: Robert Bradshaw

Issue created by migration from https://trac.sagemath.org/ticket/8254

[qed777]

comment:1

Could you provide some additional data? Which platforms? I assume that sage -startuptime does not help, or does it?

[qed777]

comment:2

By "help," I mean "help to identify the problem(s)."

[robertwb]

comment:3

OS X for one.

[sagetrac-drkirkby]

comment:4

FWIW, Sage 4.3.3 (with some mods to get it to build on Solaris) takes 8 seconds to start on a Sun Blade 1000, with 2 x 900 MHz CPUs and 2 GB RAM. That machine has 15,000 rpm 2 Gbit/s fibre channel FC-AL disks.

Considering the age of that machine, I'm not overly concerned over that one. Although this machine is quite old, the disks are quite high spec. I don't know if that gives any clues. File systems are local.

The doc test

sage -t  "devel/sage/sage/rings/polynomial/symmetric_ideal.py" 

takes 459.4 seconds to run on that machine, so this is no quick machine - I had to increase SAGE_TIMEOUT just to get some doctests to pass.

Dave

[sagetrac-drkirkby]

comment:5

Given the startup time for me, on that SPARC, and the fact I have a quicker SPARC, I'm not overly concerned by this myself.

But those interested in fixing it might like to look at using 'iostat', 'vmstat' and 'sar' to see what the system is doing.

Dave

[sagetrac-drkirkby]

comment:6

PS, that Blade 1000 of mine is using UFS disks, not ZFS. Using ZFS would take more memory from a machine that already has very little.

I suspect the startup time has more to do with disk & file-system performance than it does with CPU speed.

Dave

[robertwb]

Shaves off about 0.3 seconds for me. Depends on #8456

[williamstein]

comment:8

Attachment: 8254-lazy-schemes-import.patch.gz

I talked to Robert today and he told me thought he had marked this "needs review", but he hadn't. So I am.

[robertwb]

comment:9

Yep, this is ready for review (assuming it hasn't bitrotted). Regarding Davve Kirkby's comment, I agree that disk access is probably the main bottleneck, and this addresses that by loading fewer modules.