Occasionally useful to see one significant effect of anti-virus software.
BTW, the documentation still uses C:\cygwin as the default install directory. This is no longer the case since the retirement of the 32-bit version.
-- Regards, Christian
From a9438be956dc81ac237ef70f9c07934ba4906dae Mon Sep 17 00:00:00 2001 From: Christian Franke <christian.fra...@t-online.de> Date: Sat, 29 Mar 2025 16:34:33 +0100 Subject: [PATCH] Cygwin: faq: add test of fork/exec slowdown by anti-virus Signed-off-by: Christian Franke <christian.fra...@t-online.de> --- winsup/doc/faq-using.xml | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/winsup/doc/faq-using.xml b/winsup/doc/faq-using.xml index 4dc462a0a..e5e4479f5 100644 --- a/winsup/doc/faq-using.xml +++ b/winsup/doc/faq-using.xml @@ -956,6 +956,26 @@ contents are exempt from scanning. In a default installation, this would be <literal>C:\cygwin\bin</literal>. Obviously, this could be exploited by a hostile non-Cygwin program, so do this at your own risk. </para> +<para>Anti-virus software typically reduce the speed of Windows +<literal>CreateProcess</literal> calls which are used by Cygwin to provide +<literal>fork()</literal> and <literal>exec()</literal>. This in particular +slows down shell scripts. In the simple speed test shown below, the first +column shows the number of <literal>date</literal> commands run per second. +Anti-virus was turned off at the line marked with <literal>***</literal>. +</para> +<screen> + bash$ while :; do date +%s; done | uniq -c + ... + 122 1741712430 + 118 1741712431 + 118 1741712432 + 121 1741712433 + 142 1741712434 *** + 140 1741712435 + 141 1741712436 + 144 1741712437 + ... +</screen> <para>See also <xref linkend="faq.using.bloda"></xref> for a list of applications that have been known, at one time or another, to interfere with the normal functioning of Cygwin. -- 2.45.1
