From c7982c9e3bee93422dd140568587e2796e0c96ca Mon Sep 17 00:00:00 2001 From: "Frank Ch. Eigler" Date: Mon, 9 May 2022 19:26:07 -0400 Subject: [PATCH] debuginfod.8: Tweak wording of fdcache operation & parameters. Signed-off-by: Frank Ch. Eigler --- doc/ChangeLog | 4 ++++ doc/debuginfod.8 | 36 +++++++++++++++++++----------------- 2 files changed, 23 insertions(+), 17 deletions(-) diff --git a/doc/ChangeLog b/doc/ChangeLog index 303e3dc..cb754d0 100644 --- a/doc/ChangeLog +++ b/doc/ChangeLog @@ -1,3 +1,7 @@ +2022-05-09 Frank Ch. Eigler + + * debuginfod.8: Tweak prefetch descriptions. + 2022-01-31 Frank Ch. Eigler * debuginfod-client-config.7: Elaborate DEBUGINFOD_URLS. diff --git a/doc/debuginfod.8 b/doc/debuginfod.8 index ee8e407..95b827e 100644 --- a/doc/debuginfod.8 +++ b/doc/debuginfod.8 @@ -232,34 +232,36 @@ loops in the symbolic directory tree might lead to \fIinfinite traversal\fP. .TP -.B "\-\-fdcache\-fds=NUM" "\-\-fdcache\-mbs=MB" "\-\-fdcache\-prefetch=NUM2" +.B "\-\-fdcache\-fds=NUM" "\-\-fdcache\-mbs=MB" Configure limits on a cache that keeps recently extracted files from 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 +archives over and over 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 +most recently used extracted files are kept. Grooming cleans out this cache. .TP .B "\-\-fdcache\-\-prefetch\-fds=NUM" "\-\-fdcache\-\-prefetch\-mbs=MB" -Configure how many file descriptors (fds) and megabytes (mbs) are -allocated to the prefetch fdcache. If unspecified, values of -\fB\-\-prefetch\-fds\fP and \fB\-\-prefetch\-mbs\fP depend -on concurrency of the system and on the available disk space on -the $TMPDIR. Allocating more to the prefetch cache will improve -performance in environments where different parts of several large -archives are being accessed. +.B "\-\-fdcache\-prefetch=NUM2" + +In addition to the main fdcache, up to NUM2 other files from an +archive may be prefetched into another cache before they are even +requested. Configure how many file descriptors (fds) and megabytes +(mbs) are allocated to the prefetch fdcache. If unspecified, these +values depend on concurrency of the system and on the available disk +space on the $TMPDIR. Allocating more to the prefetch cache will +improve performance in environments where different parts of several +large archives are being accessed. This cache is also cleaned out +during grooming. .TP .B "\-\-fdcache\-mintmp=NUM" -Configure a disk space threshold for emergency flushing of the cache. -The filesystem holding the cache is checked periodically. If the -available space falls below the given percentage, the cache is -flushed, and the fdcache will stay disabled until the next groom +Configure a disk space threshold for emergency flushing of the caches. +The filesystem holding the caches is checked periodically. If the +available space falls below the given percentage, the caches are +flushed, and the fdcaches will stay disabled until the next groom cycle. This mechanism, along a few associated /metrics on the webapi, are intended to give an operator notice about storage scarcity - which can translate to RAM scarcity if the disk happens to be on a RAM -- 2.7.4