pmcferrin wrote:
> The stat(2) system call runs very slowly because it is constantlt
> triggering the McAfee on-demand virus scanner to scan the file that
> is being stat'ed. This may not seem like a big thing but I frequently
> stat thousands of files at a batch. I find that the stat runs much
> faster when I temporarily disable the on-demand virus scanner.
Judging from previous messages on this list it *seems* that one of the
slowest
things you can do in cygwin is accessing files; stat(), fopen() and the
like.
In general...
FWIW/IMO; If you have the option to replace M*Af**[1] with a just as good an
AV, then do
that - I suggest to avoid Sym*ntec[2] products too as they seem to have
similar problems.
OTOH, I have good experience with what you find at f-secure dot com - I've
had this one
installed since cygwin 1.3.x was current, and prior to that.
I've always considered S. and M. AV's to be CPU hogs in general terms - and
have found f-secure to be much lighter in this respect. Now I wonder how M.
and S. AV's compare to what I have done in a simple (attached) comparasion
with fsecure V5.30 ON/OFF
(Use e.g. NOTEPAD, and a monospace font to view it)
/H
[1] I've got previous experience with having it on my private PC.
[2] I'm forced to live with such a thing at work.
--
Test object:
Windows partition with some additional SW installed
Included on this disk is a huge cygwin installation.
Test run several times prior taking these samples.
Also making sure it ran without interference from other
running software
- this was to ensure somewhat persistent timings.
AV ON AV OFF
find =prints=> 201195 (files+dirs)
real 30.089 28.165 27.875 real 27.547 28.113 27.988
user 5.576 5.498 5.779 user 5.529 5.732 5.451
sys 23.966 22.123 21.638 sys 21.562 21.842 21.874
find - per file/dir, microseconds calculated from the above file/dir count
150 140 139 137 140 139
du -s =prints=> 7431252
real 87.608 88.285 87.523 real 43.355 41.916 41.815
user 8.155 8.03 7.89 user 7.358 8.015 7.624
sys 77.156 77.905 77.734 sys 33.531 32.062 32.312
du - per file/dir, microseconds calculated from the above file/dir count
435 439 435 215 208 208
>From this it seems that "du" does something that triggers the f-secure AV
in some way (AV doing the same as "du"?).
This has the impact of doubling the scan time per file/dir.
****
It would be interesting to see similar measurements done with McAFee and
Symantec antivirus packages.
****
-- actual test session log follows --
$ cd W: # Sempron 2800+, 1G RAM - has Win2K and related files on W:
--- AV enabled --
$ for (( i=0; i<3 ;i++ )) ;do time find 2>/dev/null -printf "%f\n" | wc -l ;done
201195
real 0m30.089s
user 0m5.576s
sys 0m23.966s
201195
real 0m28.165s
user 0m5.498s
sys 0m22.123s
201195
real 0m27.875s
user 0m5.779s
sys 0m21.638s
201195
-- AV disabled --
$ for (( i=0; i<3 ;i++ )) ;do time find 2>/dev/null -printf "%f\n" | wc -l ;done
201195
real 0m27.547s
user 0m5.529s
sys 0m21.562s
201195
real 0m28.113s
user 0m5.732s
sys 0m21.842s
201195
real 0m27.988s
user 0m5.451s
sys 0m21.874s
201195
$ for (( i=0; i<3 ;i++ )) ;do time du -s 2>/dev/null ;done
7431252 .
real 0m43.355s
user 0m7.358s
sys 0m33.531s
7431252 .
real 0m41.916s
user 0m8.015s
sys 0m32.062s
7431252 .
real 0m41.815s
user 0m7.624s
sys 0m32.312s
7431252 .
-- AV enabled --
$ for (( i=0; i<3 ;i++ )) ;do time du -s 2>/dev/null ;done
7431252 .
real 1m27.608s
user 0m8.155s
sys 1m17.156s
7431252 .
real 1m28.285s
user 0m8.030s
sys 1m17.905s
7431252 .
real 1m27.523s
user 0m7.890s
sys 1m17.734s
7431252 .
$ uname -a
CYGWIN_NT-5.0 amd 1.5.19s(0.149/4/2) 20051229 16:10:48 i686 unknown unknown
Cygwin
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