X-Recipient: archive-cygwin AT delorie DOT com
X-Spam-Check-By: sourceware.org
Message-ID: <BAY108-W25D2E2410F50C13F068CD5BE6B0@phx.gbl>
From: Mike Marchywka <marchywka AT hotmail DOT com>
To: <cygwin AT cygwin DOT com>
Subject: RE: Updated: cygwin-1.5.25-5
Date: Mon, 10 Dec 2007 08:40:37 -0500
In-Reply-To: <20071210132802.GA15065@calimero.vinschen.de>
References: <475C2AAE DOT 9030800 AT alum DOT mit DOT edu>  <20071210095725 DOT GA13109 AT calimero DOT vinschen DOT de>  <20071210132802 DOT GA15065 AT calimero DOT vinschen DOT de>
Content-Type: text/plain; charset="iso-8859-1"
MIME-Version: 1.0
X-IsSubscribed: yes
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
Precedence: bulk
List-Id: <cygwin.cygwin.com>
List-Unsubscribe: <mailto:cygwin-unsubscribe-archive-cygwin=delorie DOT com AT cygwin DOT com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
Content-Transfer-Encoding: 8bit
X-MIME-Autoconverted: from quoted-printable to 8bit by delorie.com id lBADesZg003342


> I can't reproduce worse I/O performance. I tested different scenarios
> with lots of disc I/O and the performance was identical between 1.5.24
> and 1.5.25 within the bounds of a performance test.
>


One thing I found out, after originally blaming my inner computational loops,
was that console IO is very slow. Using ">" on the command line makes a big
difference compared to opening a destination file. This seemed to be the
speed limit in many programs I thought were computationally limited. 

fwiw, I mentioned gprof to the OP earlier. I hadn't used this before but
it should give you some idea where the time goes. It may be interesting
to compare times with output sent to stdout versus a file. Obviously, you
want to flush the console more often most of the time.  Has the console buffering
changed lately? 

Also, in the past, I think std::string operations were a problem but 
I saw this in a list of bugs specific to a compiler version. 
In fact, it looks like the gprof output is given as evidence here:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15002

Mike Marchywka
586 Saint James Walk
Marietta GA 30067-7165
404-788-1216 (C)<- leave message
989-348-4796 (P)<- emergency only
marchywka AT hotmail DOT com
Note: Hotmail is blocking my mom's entire
ISP claiming it is to reduce spam but probably
to force users to use hotmail. Please DON'T
assume I am ignoring you and try
me on marchywka AT yahoo DOT com if no reply
here. Thanks.

> Date: Mon, 10 Dec 2007 14:28:02 +0100
> From: corinna-cygwin AT cygwin DOT com
> To: cygwin AT cygwin DOT com
> Subject: Re: Updated: cygwin-1.5.25-5
>
> On Dec 10 10:57, Corinna Vinschen wrote:
>> On Dec 9 10:49, Jim Reisert AD1C wrote:
>>> I have a number of data processing programs written in C in the Cygwin
>>> environment. They read data files into linked lists, analyze the data
>>> and write results back out to disk.
>>>
>>> This new release of Cygwin is about 10x slower than 1.5.24-2, after
>>> recompiling the programs. I went back to the older Cygwin release and
>>> normal speed was restored.
>>
>> Well, 10x sounds rather bad.
>
> I can't reproduce worse I/O performance. I tested different scenarios
> with lots of disc I/O and the performance was identical between 1.5.24
> and 1.5.25 within the bounds of a performance test.
>
> In some cases applications are even getting faster under 1.5.25, for
> instance cat(1) from coreutils. This is likely due to the fact that
> the st_blksize member in struct stat now returns 65536 (apparently the
> preferred I/O blocksize in Windows). This should also positively affect
> the stdio functions like fread/fwrite.
>
> Given the above, we really need a simple, self-contained testcase,
> as I asked for in my previous mail on the subject.
>
>
> Corinna
>
>
> --
> Corinna Vinschen Please, send mails regarding Cygwin to
> Cygwin Project Co-Leader cygwin AT cygwin DOT com
> Red Hat
>
> --
> Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
> Problem reports: http://cygwin.com/problems.html
> Documentation: http://cygwin.com/docs.html
> FAQ: http://cygwin.com/faq/
>

_________________________________________________________________
Your smile counts. The more smiles you share, the more we donate.  Join in.
www.windowslive.com/smile?ocid=TXT_TAGLM_Wave2_oprsmilewlhmtagline

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/