From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 60C463858C5F; Mon, 30 Oct 2023 13:30:59 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 60C463858C5F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1698672659; bh=TousXnktzBcpqov4+2rJM1t+JeBfbpV7SkPlb6eBzWA=; h=From:To:Subject:Date:In-Reply-To:References:From; b=YUK6jvdmdNDgKZssD2E/SUSEzAidu+lnBHVwg9P+UKs8bjmpawnlEwOdoXSlbFECt DvwE8S5Id05HScAOOwCyJRqLoRvbgDBMg+RK790txA2yDUOR9fbdK+okYwrM4J8AQL auHQl6/eMRPR7otNCGjS68JNo7pQuU1rSE18iLxI= From: "adhemerval.zanella at linaro dot org" To: glibc-bugs@sourceware.org Subject: [Bug string/30994] REP MOVSB performance suffers from page aliasing on Zen 4 Date: Mon, 30 Oct 2023 13:30:58 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: glibc X-Bugzilla-Component: string X-Bugzilla-Version: 2.38 X-Bugzilla-Keywords: X-Bugzilla-Severity: minor X-Bugzilla-Who: adhemerval.zanella at linaro dot org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at sourceware dot org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: security- X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: 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 List-Id: https://sourceware.org/bugzilla/show_bug.cgi?id=3D30994 --- Comment #10 from Adhemerval Zanella --- On Zen3 I am not seeing such slowdown using vectorized instructions. With a patch glibc to disable REP MOVSB I see: $ ./testrun.sh ./memcpy_loop -D 512 -b 4096 -t mmap_huge -f memcpy -p 10000= 000 146.593 GB/s # Force REP MOVSB $ GLIBC_TUNABLES=3Dglibc.cpu.x86_rep_movsb_stop_threshold=3D4097 ./testrun.= sh ./memcpy_loop -D 512 -b 4096 -t mmap_huge -f memcpy -p 10000000 116.298 GB/s And I don't see difference between mmap and mmap_huge. --=20 You are receiving this mail because: You are on the CC list for the bug.=