Zsh filename completion sluggishness?

[Jason Tiller <jtiller at sjm dot com>]

Hello, All, :)

[Pardon me if I'm asking this in the wrong place.  I thought to check
here before going to the Zsh Users list.]

For the last week or so I've been experimenting with Zsh as a
replacement for bash, mainly because of Zsh's adherents claim that
it's the most powerful shell for interactive, command-line use.  I
come from JPSoft's fabulous 4{DOS,NT} interpreter, which was really a
command-line junkie's dream.  As an example, Zsh's "AUTO_CD" feature
is the only place I've seen 4NT's functionality mimicked (disregarding
its actual heritage - 4NT may have stolen it from Zsh or some other
shell), and it's *so* handy for fast touch-typists.

However, Zsh seems painfully *slow*.  I'm using a recent Cygwin
refresh (1.3.19-1) with Zsh-4.0.6-3, and the amount of time it takes
Zsh to complete a directory name for 'cd', for example, is painful.
When I say it takes 2 seconds, that may not *seem* long, but when when
I'm typing

cd /q/de<tab>/neu<tab>/emt<tab>/co<tab>/hs

and each of those <tab>s takes two seconds, I'm frustrated when I
finally reach the end.

The slowness is especially evident on remote drives, such as NT shares
or (God forbid) ClearCase dynamic views (::sigh::).

Bash (2.05b-8) does not seem to suffer from this slow filename
completion problem.  I decided to do an strace of what happens in this
situation:

18 13:47 /q/devtools/Neutrino/EmtPlus/vtest
$ ls
BAR      DIOPAT                         Ep        Per      tools
BlueBox  DO                             HS        Summary  unittest
Cfp      Das                            HW        Tst      zerobat_results.zip
Com      Ddp                            IntgTest  UI       zeromem.zip
DI       EMTPlus_descrepancy_table.doc  Lac       issues

19 13:47 /q/devtools/Neutrino/EmtPlus/vtest
$ cd C<tab>

I used strace -p <pid> to attach to the running process just before
pressing the <tab> key; that's pretty much all I did.  Just for a
simple comparison, look at this:

$ ls -l bash_cd.txt zsh_cd.txt
-rw-r--r--    1 TilleJ01 mkgroup     13098 Feb 13 13:51 bash_cd.txt
-rw-r--r--    1 TilleJ01 mkgroup    309029 Feb 13 13:00 zsh_cd.txt

Yes, Zsh's strace output is nearly *25* times larger.  Looking at the
strace outputs more carefully, the Zsh trace has this near the
beginning:

  117 3006802 [main] zsh 276 set_process_mask: old mask = 80000, new mask = 8000
   98 3006900 [main] zsh 276 set_process_mask: not calling sig_dispatch_pending.
   98 3006998 [main] zsh 276 set_process_mask: old mask = 80000, new mask = 0
  101 3007099 [main] zsh 276 set_process_mask: old mask = 0, new mask = 80000
  314 3007413 [main] zsh 276 set_process_mask: old mask = 80000, new mask = 8000
  106 3007519 [main] zsh 276 set_process_mask: not calling sig_dispatch_pending.
This goes on for almost 600 lines.  Any idea what's happening here?

Both shells get to the "normalize_posix_path" function *eventually*,
but it takes bash 1 line after the keystroke read to get there,
whereas it takes Zsh almost 600.

I sorted the strace output to get an idea of what functions where
taking so long (except for the keyboard read, obviously).  The longest
function called in bash takes around 10000 whatevers (usecs?).  The
longest function called in zsh takes 25000 units!  And zsh calls 23
functions that all take longer than the slowest bash-called function.

The long zsh functions where:

10090 9076054 [main] zsh 276 set_process_mask: old mask = 80000, new mask = 80000
10106 3406991 [main] zsh 276 fhandler_disk_file::fstat_by_handle: 1 = GetFileInformationByHandle (q:\devtools\Neutrino\EmtPlus\vtest\DIOPAT, 632)
10344 9663796 [main] zsh 276 symlink_info::check: not a symlink
10348 3018272 [main] zsh 276 set_process_mask: old mask = 80000, new mask = 80000
10415 3439329 [main] zsh 276 symlink_info::check: not a symlink
10488 3717050 [main] zsh 276 symlink_info::check: not a symlink
10513 3323802 [main] zsh 276 fhandler_disk_file::fstat_by_handle: 1 = GetFileInformationByHandle (q:\devtools\Neutrino\EmtPlus\vtest\Com, 632)
10667 3365868 [main] zsh 276 fhandler_disk_file::fstat_by_handle: 1 = GetFileInformationByHandle (q:\devtools\Neutrino\EmtPlus\vtest\Ddp, 632)
10738 9445834 [main] zsh 276 symlink_info::check: not a symlink
12178 9128080 [main] zsh 276 set_process_mask: old mask = 0, new mask = 80000
12606 9462770 [main] zsh 276 fhandler_disk_file::fstat_by_handle: 1 = GetFileInformationByHandle (q:\devtools\Neutrino\EmtPlus\vtest\EMTPlus_descrepancy_table.doc, 772)
12746 3456301 [main] zsh 276 fhandler_disk_file::fstat_by_handle: 1 = GetFileInformationByHandle (q:\devtools\Neutrino\EmtPlus\vtest\EMTPlus_descrepancy_table.doc, 632)
12751 9681534 [main] zsh 276 fhandler_disk_file::fstat_by_handle: 1 = GetFileInformationByHandle (q:\devtools\Neutrino\EmtPlus\vtest\zerobat_results.zip, 772)
12763 3733960 [main] zsh 276 fhandler_disk_file::fstat_by_handle: 1 = GetFileInformationByHandle (q:\devtools\Neutrino\EmtPlus\vtest\zerobat_results.zip, 632)
14121 9060702 [main] zsh 276 set_process_mask: old mask = 0, new mask = 80000
14212 3130669 [main] zsh 276 set_process_mask: not calling sig_dispatch_pending.  sigtid 0x674 current 0x3D8
14525 3002672 [main] zsh 276 set_process_mask: old mask = 0, new mask = 80000
148890 9040940 [main] zsh 276 fhandler_tty_slave::read: reading 1 bytes (vtime 0)
15053 9735219 [main] zsh 276 set_process_mask: old mask = 0, new mask = 80000
15148 3794233 [main] zsh 276 set_process_mask: old mask = 0, new mask = 80000
20983 9810694 [main] zsh 276 dtable::dup2: dup2 (11, 0)
21450 3883879 [main] zsh 276 dtable::dup2: dup2 (11, 0)
25177 3862001 [main] zsh 276 set_process_mask: old mask = 0, new mask = 80000
25632 9789337 [main] zsh 276 set_process_mask: old mask = 0, new mask = 80000

The long bash functions were:

 1022 1696574 [main] bash 1788 stat64: entering
 1439 1674237 [main] bash 1788 normalize_posix_path: src .
 3303 1741238 [main] bash 1788 stat64: entering
 5198 1747773 [main] bash 1788 symlink_info::check: not a symlink
 7243 1756457 [main] bash 1788 fhandler_disk_file::fstat_by_handle: 1 = GetFileInformationByHandle (q:\devtools\Neutrino\EmtPlus\Vtest\Cfp, 880)
 7628 1725872 [main] bash 1788 symlink_info::check: not a symlink
 7804 1705159 [main] bash 1788 symlink_info::check: not a symlink
 7899 1682764 [main] bash 1788 symlink_info::check: not a symlink
 7931 1691582 [main] bash 1788 fhandler_disk_file::readdir: 0xA056704 = readdir (0xA056700) (.)
 9678 1716326 [main] bash 1788 fhandler_disk_file::fstat_by_handle: 1 = GetFileInformationByHandle (q:\devtools\Neutrino\EmtPlus\Vtest\Cfp, 880)
 9939 1737413 [main] bash 1788 fhandler_disk_file::fstat_by_handle: 1 = GetFileInformationByHandle (q:\devtools\Neutrino\EmtPlus\Vtest\Com, 880)

You can see just *how* *much* *faster* bash is vs. zsh.  I'm sure
something's wrong in my configuration... right?

Does anyone have any ideas how I can speed up Zsh's completion?  I
love the facilities Zsh provides, but unless I can tune it up somehow,
it's back to bash for me.

Thanks in advance for any help.  If people suggest that I reflect this
discussion to the Zsh User's, I'll do so.

---Jason
Sonos Handbell Ensemble
http://www.sonos.org/


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