PR25375: fdcache prefetching to reduce repeated archive decompression

Introduce new option --fdcache-prefetch to accelerate repeated
queries from the same debuginfo archive.

Signed-off-by: Frank Ch. Eigler <fche@redhat.com>

1 files changed, 10 insertions, 7 deletions

diff --git a/doc/debuginfod.8 b/doc/debuginfod.8
index ca844aed..ed9724d6 100644
--- a/doc/debuginfod.8
+++ b/doc/debuginfod.8
@@ -193,14 +193,17 @@ loops in the symbolic directory tree might lead to \fIinfinite
 traversal\fP.
 
 .TP
-.B "\-\-fdcache-fds=NUM"  "\-\-fdcache-mbs=MB"
+.B "\-\-fdcache\-fds=NUM"  "\-\-fdcache\-mbs=MB"  "\-\-fdcache\-prefetch=NUM2"
 Configure limits on a cache that keeps recently extracted files from
-archives.  Up to NUM files and up to a total of MB megabytes will be
-kept extracted, in order to avoid having to decompress their archives
-again.  The default NUM and MB values depend on the concurrency of the
-system, and on the available disk space on the $TMPDIR or \fB/tmp\fP
-filesystem.  This is because that is where the most recently used
-extracted files are kept.  Grooming cleans this cache.
+archives.  Up to NUM requested files and up to a total of MB megabytes
+will be kept extracted, in order to avoid having to decompress their
+archives over and over again.  In addition, up to NUM2 other files
+from an archive may be prefetched into the cache before they are even
+requested.  The default NUM, NUM2, and MB values depend on the
+concurrency of the system, and on the available disk space on the
+$TMPDIR or \fB/tmp\fP filesystem.  This is because that is where the
+most recently used extracted files are kept.  Grooming cleans this
+cache.
 
 .TP
 .B "\-v"