sub[ug]id manpages: add note about performance when using login names versus UIDs

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

diff --git a/man/subgid.5.xml b/man/subgid.5.xml
index 27799ba9338748e994ce3cce12a1555d3f1344c7..ffdb7d802dedb3a5fc5722486a9b20cd8d68a7b3 100644 (file)
--- a/man/subgid.5.xml
+++ b/man/subgid.5.xml
@@ -77,6 +77,13 @@
       Multiple ranges may be specified per user.
     </para>
 
+    <para>
+      When large number of entries (10000-100000 or more) are defined in
+      <filename>/etc/subgid</filename>, parsing performance penalty will
+      become noticeable. In this case it is recommended to use UIDs
+      instead of login names. Benchmarks have shown speed-ups up to 20x.
+    </para>
+
   </refsect1>
 
   <refsect1 id='files'>

diff --git a/man/subuid.5.xml b/man/subuid.5.xml
index 939ea166ef40571fa4bcdb2b6eceb7f358d2f966..2890661df944383b976b11fac1503c803417cff2 100644 (file)
--- a/man/subuid.5.xml
+++ b/man/subuid.5.xml
@@ -77,6 +77,13 @@
       Multiple ranges may be specified per user.
     </para>
 
+    <para>
+      When large number of entries (10000-100000 or more) are defined in
+      <filename>/etc/subuid</filename>, parsing performance penalty will
+      become noticeable. In this case it is recommended to use UIDs
+      instead of login names. Benchmarks have shown speed-ups up to 20x.
+    </para>
+
   </refsect1>
 
   <refsect1 id='files'>