From 98d778eeae63428721b900ca1b8c4972966d8395 Mon Sep 17 00:00:00 2001 From: Clayton Craft Date: Mon, 12 Apr 2021 16:24:35 -0700 Subject: [PATCH] widgets/terminal: Only call vterm.ScreenCell.Attrs once in styleFromCell This fixes a substantial performance issue when scrolling emails with long/complicated contents, where scrolling down a single line can take something like hundreds of ms before the screen is updated to reflect the scroll. It's really bad if the email has lots of columns, e.g. like if it's an html email that was passed through a filter (w3m, etc) to render it. Using pprof, I found that the multiple calls to vterm.ScreenCell.Attrs() in styleFromCell were really really expensive. This patch replaces them with a single call. Here's a before and after with a simple, but very manual test of opening a large email with contents that went through a w3m filter and continuously scrolling up and down over and over for ~30 seconds: *** Before: ----------------------------------------------------------+------------- flat flat% sum% cum cum% calls calls% + context ----------------------------------------------------------+------------- 28.25s 100% | git.x2esr.x2eht..z2f..z7esircmpwn..z2faerc..z2fwidgets.PartSwitcher.Draw 0 0% 99.94% 28.25s 82.31% | git.x2esr.x2eht..z2f..z7esircmpwn..z2faerc..z2fwidgets.PartViewer.Draw 28.25s 100% | git.x2esr.x2eht..z2f..z7esircmpwn..z2faerc..z2fwidgets.Terminal.Draw ----------------------------------------------------------+------------- 28.25s 100% | git.x2esr.x2eht..z2f..z7esircmpwn..z2faerc..z2fwidgets.PartViewer.Draw 0 0% 99.94% 28.25s 82.31% | git.x2esr.x2eht..z2f..z7esircmpwn..z2faerc..z2fwidgets.Terminal.Draw 19.23s 68.07% | git.x2esr.x2eht..z2f..z7esircmpwn..z2faerc..z2fwidgets.Terminal.styleFromCell 6.04s 21.38% | github.x2ecom..z2fddevault..z2fgo..z2dlibvterm.Screen.GetCellAt 1.38s 4.88% | git.x2esr.x2eht..z2f..z7esircmpwn..z2faerc..z2flib..z2fui.Context.Printf 0.62s 2.19% | runtime.mapassign 0.43s 1.52% | runtime.mapaccess2 0.20s 0.71% | runtime.newobject 0.19s 0.67% | runtime.callers (inline) 0.07s 0.25% | runtime.makeslice 0.07s 0.25% | runtime.mallocgc ----------------------------------------------------------+------------- 19.23s 100% | git.x2esr.x2eht..z2f..z7esircmpwn..z2faerc..z2fwidgets.Terminal.Draw 0 0% 99.94% 19.23s 56.03% | git.x2esr.x2eht..z2f..z7esircmpwn..z2faerc..z2fwidgets.Terminal.styleFromCell 19.21s 99.90% | github.x2ecom..z2fddevault..z2fgo..z2dlibvterm.ScreenCell.Attrs *** After: ----------------------------------------------------------+------------- flat flat% sum% cum cum% calls calls% + context ----------------------------------------------------------+------------- 0.31s 100% | git.x2esr.x2eht/~sircmpwn/aerc/widgets.Terminal.Draw 0 0% 99.87% 0.31s 1.33% | github.x2ecom/ddevault/go-libvterm.NewPos 0.25s 80.65% | runtime.callers (inline) 0.04s 12.90% | runtime.gomcache (inline) ----------------------------------------------------------+------------- 8.40s 100% | github.x2ecom/ddevault/go-libvterm.Screen.GetCellAt 0 0% 99.87% 8.40s 36.11% | github.x2ecom/ddevault/go-libvterm.Screen.GetCell 7.14s 85.00% | github.x2ecom/ddevault/go-libvterm._cgoCheckPointer 0.54s 6.43% | runtime.callers (inline) 0.35s 4.17% | runtime.exitsyscall 0.11s 1.31% | runtime.deferprocStack 0.07s 0.83% | doentersyscall 0.07s 0.83% | runtime.getg 0.05s 0.6% | runtime.casgstatus 0.03s 0.36% | _init 0.03s 0.36% | runtime.gomcache (inline) ----------------------------------------------------------+------------- 8.46s 100% | git.x2esr.x2eht/~sircmpwn/aerc/widgets.Terminal.Draw 0 0% 99.87% 8.46s 36.37% | github.x2ecom/ddevault/go-libvterm.Screen.GetCellAt 8.40s 99.29% | github.x2ecom/ddevault/go-libvterm.Screen.GetCell 0.06s 0.71% | runtime.callers (inline) ----------------------------------------------------------+------------- 0.31s 100% | git.x2esr.x2eht/~sircmpwn/aerc/widgets.Terminal.styleFromCell 0 0% 99.87% 0.31s 1.33% | github.x2ecom/ddevault/go-libvterm.ScreenCell.Attrs ) --- widgets/terminal.go | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/widgets/terminal.go b/widgets/terminal.go index f47f671..920c312 100644 --- a/widgets/terminal.go +++ b/widgets/terminal.go @@ -9,7 +9,7 @@ import ( "git.sr.ht/~sircmpwn/aerc/lib/ui" "github.com/creack/pty" - "github.com/ddevault/go-libvterm" + vterm "github.com/ddevault/go-libvterm" "github.com/gdamore/tcell/v2" ) @@ -422,20 +422,21 @@ func (term *Terminal) styleFromCell(cell *vterm.ScreenCell) tcell.Style { } style = style.Background(bg).Foreground(fg) + attrs := cell.Attrs() - if cell.Attrs().Bold != 0 { + if attrs.Bold != 0 { style = style.Bold(true) } - if cell.Attrs().Italic != 0 { + if attrs.Italic != 0 { style = style.Italic(true) } - if cell.Attrs().Underline != 0 { + if attrs.Underline != 0 { style = style.Underline(true) } - if cell.Attrs().Blink != 0 { + if attrs.Blink != 0 { style = style.Blink(true) } - if cell.Attrs().Reverse != 0 { + if attrs.Reverse != 0 { style = style.Reverse(true) } return style