From a2d78fba200d0342d90cf27f2ac3eb9091911275 Mon Sep 17 00:00:00 2001 From: Austin Clements Date: Tue, 8 Nov 2011 21:55:28 -0500 Subject: [PATCH] emacs: Use a single buffer invisibility spec to fix quadratic search cost. Buffer redisplay requires traversing the buffer's invisibility spec for every part of the display that has an 'invisible text or overlay property. Previously, the search buffer's invisibility spec list contained roughly one entry for each search result. As a result, redisplay took O(NM) time where N is the number of visible lines and M is the total number of results. On a slow computer, this is enough to make even buffer motion noticeably slow. Worse, during a search operation, redisplay is triggered for each search result (even if there are no visible buffer changes), so search was quadratic (O(NM^2)) in the number of search results. This change switches to using a single element buffer invisibility spec. To un-hide authors, instead of removing an entry from the invisibility spec, it simply removes the invisibility overlay from those authors. I tested using a query with 6633 results on a 9 year old machine. Before this patch, Emacs took 70 seconds to fill the search buffer; toward the end of the search, Emacs consumed 10-20x as much CPU as notmuch; and moving point in the buffer took about a second. With this patch, the same query takes 40 seconds, Emacs consumes ~3x the CPU of notmuch by the end, and there's no noticeable lag to moving point. (There's still some source of non-linearity, because Emacs and notmuch consume roughly the same amount of CPU early in the search.) --- emacs/notmuch.el | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/emacs/notmuch.el b/emacs/notmuch.el index 456c7830..c5741b7f 100644 --- a/emacs/notmuch.el +++ b/emacs/notmuch.el @@ -378,7 +378,7 @@ Complete list of currently available key bindings: (make-local-variable 'notmuch-search-target-line) (set (make-local-variable 'notmuch-search-continuation) nil) (set (make-local-variable 'scroll-preserve-screen-position) t) - (add-to-invisibility-spec 'notmuch-search) + (add-to-invisibility-spec (cons 'ellipsis t)) (use-local-map notmuch-search-mode-map) (setq truncate-lines t) (setq major-mode 'notmuch-search-mode @@ -679,9 +679,6 @@ foreground and blue background." (append (overlay-get overlay 'face) attributes))))) notmuch-search-line-faces))) -(defun notmuch-search-isearch-authors-show (overlay) - (remove-from-invisibility-spec (cons (overlay-get overlay 'invisible) t))) - (defun notmuch-search-author-propertize (authors) "Split `authors' into matching and non-matching authors and propertize appropriately. If no boundary between authors and @@ -755,13 +752,11 @@ non-authors is found, assume that all of the authors match." (insert visible-string) (when (not (string= invisible-string "")) (let ((start (point)) - (invis-spec (make-symbol "notmuch-search-authors")) overlay) (insert invisible-string) - (add-to-invisibility-spec (cons invis-spec t)) (setq overlay (make-overlay start (point))) - (overlay-put overlay 'invisible invis-spec) - (overlay-put overlay 'isearch-open-invisible #'notmuch-search-isearch-authors-show))) + (overlay-put overlay 'invisible 'ellipsis) + (overlay-put overlay 'isearch-open-invisible #'delete-overlay))) (insert padding)))) (defun notmuch-search-insert-field (field date count authors subject tags)