Xz compression format software#

The use of the LZO compression offers 40-74% cold startup improvements over the XZ compression.

The standard deviation is ~0.7 seconds for the cold startups, and ~0.1 seconds for the hot startups.

The results in the table are average values over multiple runs.

Please note that these results are highly indicative, but there is always a degree of variance in interactive usage measurements, which can result from things like your overall system state, the current system load due to other, background activities, disk usage, your browser profile and add-ons, and other factors. We measured the startup time for the Chromium browser with a new, unused profile.

Hot start – The browser data is cached in the memory.

Cold start – There is no cached data in the memory.

We compared the results in the following way:

Snap with LZO compression (all systems).Snap with XZ compression (all systems).Native package (DEB or RPM) where available (Kubuntu 18.04 and Fedora 32).On each of the selected systems, we examined the time it takes to launch and display the browser window for: System 4 with 4-core/8-thread Intel(R) i7(TM) processor, 64GB RAM, 1TB NVMe hard disk, and Nvidia GM204M (GeForce GTX 980M), running Ubuntu 20.10.System 3 with 4-core Intel(R) i3(TM) processor, 4GB RAM, 1TB 5,400rpm mechanical hard disk, and Intel(R) HD 440 graphics, running Fedora 32 Workstation.System 2 with 4-core Intel(R) i3(TM) processor, 4GB RAM, 1TB 5,400rpm mechanical hard disk, and Intel(R) HD 440 graphics, running Ubuntu 20.04 LTS.System 1 with 4-core/8-thread Intel(R) i5(TM) processor, 16GB RAM, 500GB SSD, and Intel(R) UHD 620 graphics, running Kubuntu 18.04.We believe this offers a good mix of hardware and software, allowing us a broader understanding of our work. We decided to conduct the testing on a range of systems (2015-2020 laptop models), including HDD, SSD and NVMe storage, Intel and Nvidia graphics, as well as several operating systems, including Kubuntu 18.04, Ubuntu 20.04 LTS, Ubuntu 20.10 (pre-release at the time of writing), and Fedora 32 Workstation (just before Fedora 33 release). Three, it is not part of any specific Linux desktop environment, which makes the testing independent and accurate.įor comparison, the XZ-compressed snap weighs ~150 MB, whereas the one using the LZO compression is ~250 MB in size. Two, Chromium is a relatively large and complex application. One, the browser is a ubiquitous (and popular) application, with frequent usage, so any potential slowness is likely to be noticeable. We believe this is a highly representative case, for several reasons. The LZO algorithm was selected because it offers the highest level of compatibility over a number of different use cases.Īs a test case, we chose the Chromium browser (stable build, 85.X). To improve startup times, we decided to test a different algorithm – LZO – which offers lesser compression, but needs less processing power to complete the action. Subsequent launches are fast and typically, there’s little to no difference compared to traditionally packaged applications.

This is also far more noticeable on first launch only, before the application data is cached in memory. On the desktops, users may perceive this as a “slowness” – the time it takes for the application to launch. This results in a high level of compression but consequently requires more processing power to uncompress and expand the filesystem for use. Now, we want to tell you about another major milestone – the use of a new compression algorithm for snaps offers 2-3x improvement in application startup times! LZO and XZ algorithmsīy default, snaps are packaged as a compressed, read-only squashfs filesystem using the XZ algorithm. Last year, we talked about improved snap startup times following fontconfig cache optimization.

We are well aware of this phenomenon, and we have invested significant effort and time in resolving any speed gaps, while keeping security in mind. Snaps are self-contained applications, with layered security, and as a result, sometimes, they may have reduced perceived performance compared to those same applications offered via traditional Linux packaging mechanisms.

Xz compression format software#

A great user experience is one that manages to blend the two in a way that does not compromise on robust, solid foundations of security on one hand, and a fast, responsive software interaction on the other. Security and performance are often mutually exclusive concepts. Snap speed improvements with new compression algorithm!