From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <dwz-return-486-listarch-dwz=sourceware.org@sourceware.org>
Received: (qmail 93287 invoked by alias); 29 Nov 2019 12:15:59 -0000
Mailing-List: contact dwz-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <dwz.sourceware.org>
List-Post: <mailto:dwz@sourceware.org>
List-Help: <mailto:dwz-help@sourceware.org>
List-Subscribe: <mailto:dwz-subscribe@sourceware.org>
Sender: dwz-owner@sourceware.org
Received: (qmail 93245 invoked by uid 48); 29 Nov 2019 12:15:51 -0000
From: "vries at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>
To: dwz@sourceware.org
Subject: [Bug default/25231] Reuse checksums
Date: Tue, 01 Jan 2019 00:00:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: dwz
X-Bugzilla-Component: default
X-Bugzilla-Version: unspecified
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: enhancement
X-Bugzilla-Who: vries at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: nobody at sourceware dot org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-25231-11298-BkxNn76YJW@http.sourceware.org/bugzilla/>
In-Reply-To: <bug-25231-11298@http.sourceware.org/bugzilla/>
References: <bug-25231-11298@http.sourceware.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://sourceware.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2019-q4/txt/msg00101.txt.bz2

https://sourceware.org/bugzilla/show_bug.cgi?id=3D25231

--- Comment #1 from Tom de Vries <vries at gcc dot gnu.org> ---
(In reply to Tom de Vries from comment #0)
> That difference is caused by handling of DW_FORM_strp, which is encoded i=
nto
> the checksum using the index to the string table rather than the string
> contents, which is a speed optimization for regular-mode (but which assum=
es
> that the input file is optimally encoded, in the sense that each unique
> string is encoded either using DW_FORM_strp, or DW_FORM_string, but not
> both).

FTR, naively disabling this optimization makes no difference in the result =
for
cc1 and comes at a 5% execution time penalty:
...
series:  5630 5502 5510 5502 5521 5517 5521 5517 5486 5525
mean:  5523.10 (100%)
stddev:  39.37
series:  5877 5794 5832 5780 5811 5802 5769 5812 5845 5788
mean:  5811.00 (105.21%)
stddev:  32.62
user:
series:  5321 5326 5274 5258 5305 5319 5292 5300 5285 5299
mean:  5297.90 (100%)
stddev:  21.57
series:  5560 5546 5655 5531 5595 5554 5564 5568 5616 5555
mean:  5574.40 (105.22%)
stddev:  37.25
sys:
series:  308 176 236 244 216 196 228 216 200 224
mean:  224.40 (100%)
stddev:  35.60
series:  316 248 176 248 216 248 204 244 228 232
mean:  236.00 (105.17%)
stddev:  36.51
...

--=20
You are receiving this mail because:
You are on the CC list for the bug.