On Fri, 29 Oct 2021 10:35:08 +0100 Eliot Moss wrote: > I think a lot of us know that fork() under Cygwin is slower than on Linux and > have some grasp of why. But I have noticed that file access is rather lower > under Cygwin as well. My "poster child" for this is running latex. I am > working on writing a book, which includes a huge number of LaTeX style files > and such. Under WSL1 (which has the same fork cost issues as Cygwin for > similar reasons), reading the style files goes by in little more than the > blink of an eye (about 1 sec), while on Cygwin it takes a little over 17 > seconds. > > The time to process the body of the book is 23 seconds under WSL1 and 35 under > Cygwin. So the total times are 53 seconds under Cygwin and 24 under WSL1. I > believe the LaTeX installations are the same versions, and I get the same > outputs. Both LaTeX's are 64 bit programs. There is not much forking here > (at least I don't believe there is, but maybe there is under the cover for > doing things with pdf figures or something), but a fair amount of file I/O. > > For many / most things, the Cygwin overhead is tolerable; for running this > book, since I will be doing it over and over, it was worth investing in > getting everything set up on WSL1. > > But it got me wondering as to why?
Why do you think the cause is the file access performance? I tested the file access speed using dd as follows. In cygwin: [yano@Express5800-S70 ~]$ dd if=/dev/zero of=test.dat bs=1M count=500 500+0 records in 500+0 records out 524288000 bytes (524 MB, 500 MiB) copied, 0.186714 s, 2.8 GB/s [yano@Express5800-S70 ~]$ dd if=test.dat of=/dev/null bs=1M count=500 500+0 records in 500+0 records out 524288000 bytes (524 MB, 500 MiB) copied, 0.125709 s, 4.2 GB/s In WSL1: Express5800-S70:~> dd if=/dev/zero of=test.dat bs=1M count=500 500+0 records in 500+0 records out 524288000 bytes (524 MB, 500 MiB) copied, 0.301657 s, 1.7 GB/s Express5800-S70:~> dd if=test.dat of=/dev/null bs=1M count=500 500+0 records in 500+0 records out 524288000 bytes (524 MB, 500 MiB) copied, 0.229617 s, 2.3 GB/s The result shows the file access performance of cygwin is better than WSL1. I think the cause of your problem is something other than file access performance. -- Takashi Yano <takashi.y...@nifty.ne.jp> -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
