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merge: mark file gets as not thread safe (issue5933)...
merge: mark file gets as not thread safe (issue5933) In default installs, this has the effect of disabling the thread-based worker on Windows when manifesting files in the working directory. My measurements have shown that with revlog-based repositories, Mercurial spends a lot of CPU time in revlog code resolving file data. This ends up incurring a lot of context switching across threads and slows down `hg update` operations when going from an empty working directory to the tip of the repo. On mozilla-unified (246,351 files) on an i7-6700K (4+4 CPUs): before: 487s wall after: 360s wall (equivalent to worker.enabled=false) cpus=2: 379s wall Even with only 2 threads, the thread pool is still slower. The introduction of the thread-based worker (02b36e860e0b) states that it resulted in a "~50%" speedup for `hg sparse --enable-profile` and `hg sparse --disable-profile`. This disagrees with my measurement above. I theorize a few reasons for this: 1) Removal of files from the working directory is I/O - not CPU - bound and should benefit from a thread pool (unless I/O is insanely fast and the GIL release is near instantaneous). So tests like `hg sparse --enable-profile` may exercise deletion throughput and aren't good benchmarks for worker tasks that are CPU heavy. 2) The patch was authored by someone at Facebook. The results were likely measured against a repository using remotefilelog. And I believe that revision retrieval during working directory updates with remotefilelog will often use a remote store, thus being I/O and not CPU bound. This probably resulted in an overstated performance gain. Since there appears to be a need to enable the thread-based worker with some stores, I've made the flagging of file gets as thread safe configurable. I've made it experimental because I don't want to formalize a boolean flag for this option and because this attribute is best captured against the store implementation. But we don't have a proper store API for this yet. I'd rather cross this bridge later. It is possible there are revlog-based repositories that do benefit from a thread-based worker. I didn't do very comprehensive testing. If there are, we may want to devise a more proper algorithm for whether to use the thread-based worker, including possibly config options to limit the number of threads to use. But until I see evidence that justifies complexity, simplicity wins. Differential Revision: https://phab.mercurial-scm.org/D3963

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HGAnnotate.vim
27 lines | 859 B | text/x-vim | VimLexer
" $Id: CVSAnnotate.vim,v 1.5 2002/10/01 21:34:02 rhiestan Exp $
" Vim syntax file
" Language: CVS annotate output
" Maintainer: Bob Hiestand <bob@hiestandfamily.org>
" Last Change: $Date: 2002/10/01 21:34:02 $
" Remark: Used by the cvscommand plugin. Originally written by Mathieu
" Clabaut
if version < 600
syntax clear
elseif exists("b:current_syntax")
finish
endif
syn match cvsDate /\S\S\S \S\+ \d\+ \d\+:\d\+:\d\+ \d\+ [+-]\?\d\+/ contained
syn match cvsName /^\s*\S\+ / contained nextgroup=cvsVer
syn match cvsVer /\d\+ / contained nextgroup=cvsDate
syn region cvsHead start="^" end=":" contains=cvsVer,cvsName,cvsDate
if !exists("did_cvsannotate_syntax_inits")
let did_cvsannotate_syntax_inits = 1
hi link cvsText String
hi link cvsDate Comment
hi link cvsName Type
hi link cvsVer Statement
endif
let b:current_syntax="CVSAnnotate"