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From: rth@gcc.gnu.org
To: gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, leitner@fefe.de,
	nobody@gcc.gnu.org
Subject: Re: libstdc++/4150: catastrophic performance decrease in C++ code
Date: Thu, 11 Apr 2002 17:19:00 -0000	[thread overview]
Message-ID: <20020412001906.17101.qmail@sources.redhat.com> (raw)

Synopsis: catastrophic performance decrease in C++ code

State-Changed-From-To: open->analyzed
State-Changed-By: rth
State-Changed-When: Thu Apr 11 17:19:06 2002
State-Changed-Why:
    Still present in 3.1.  We're seeking unnecessarily, even after
    adding a sync_with_stdio(false) to the source (which I now attach
    to the PR).  Strace shows
    
    _llseek(4, 8192, {8192}, SEEK_SET)      = 0
    read(4, "AOL (Traffic-Server/1.1.6 [1])\""..., 8192) = 8192
    _llseek(4, 8192, {8192}, SEEK_SET)      = 0
    _llseek(4, 16384, {16384}, SEEK_SET)    = 0
    read(4, "cur=0&skip=10\" \"Mozilla/4.0 (c"..., 8192) = 8192
    _llseek(4, 16384, {16384}, SEEK_SET)    = 0
    
    which indeed agrees with what basic_filebuf<>::underflow is
    doing.  To my mind this is appalling waste.  Surely this is
    not necessary when sync is off?

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=4150


             reply	other threads:[~2002-04-12  0:19 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-04-11 17:19 rth [this message]
2002-04-11 18:20 ljrittle
2002-04-14 11:13 jason
2002-04-14 19:36 Jason Merrill
2002-04-15  7:42 jason
2002-04-15 16:16 Jason Merrill
2002-04-16  5:46 Jason Merrill
2002-04-17 19:26 Jason Merrill
2002-04-17 21:56 Benjamin Kosnik
2002-04-18  3:06 Jason Merrill
2002-04-18  4:06 Jason Merrill
2002-04-23  5:23 jason

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