From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=dUjR=7Q=xry111.site=xry111@sourceware.org>
Received: from xry111.site (xry111.site [89.208.246.23])
	by sourceware.org (Postfix) with ESMTPS id 775853858CDA
	for <libc-alpha@sourceware.org>; Fri, 24 Mar 2023 10:36:52 +0000 (GMT)
DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 775853858CDA
Authentication-Results: sourceware.org; dmarc=pass (p=reject dis=none) header.from=xry111.site
Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=xry111.site
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=xry111.site;
	s=default; t=1679654211;
	bh=MFo81P6LLIkUGMozcS8JyLw7SnVXxDm+vRkzdP/i+ds=;
	h=Subject:From:To:Cc:Date:In-Reply-To:References:From;
	b=GWOJ02wzJZOiHrwEgKgAL1CHm3tpwLFD3Eib0+UHBaLx7yH10pyOd14craQqaNl9t
	 1Z2YIwFM5565tNvMBd0DsdUcDTzmv3IXHffXhDrR9OAK6jhSHlu4ISPy55LSab/cfl
	 sgpXD139W94FgiRTglvDrD+MHeI6FbzRDgmKPd94=
Received: from [IPv6:2408:8471:1010:525f:49d1:966f:19a1:bf95] (unknown [IPv6:2408:8471:1010:525f:49d1:966f:19a1:bf95])
	(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
	 key-exchange ECDHE (P-256) server-signature ECDSA (P-384) server-digest SHA384)
	(Client did not present a certificate)
	(Authenticated sender: xry111@xry111.site)
	by xry111.site (Postfix) with ESMTPSA id 152DE65C45;
	Fri, 24 Mar 2023 06:36:47 -0400 (EDT)
Message-ID: <30790befdca73a5224b5a9a4491821e33cccc771.camel@xry111.site>
Subject: Re: [PATCH] linux: Allow avoiding va_list for generic syscall and
 use it for LoongArch
From: Xi Ruoyao <xry111@xry111.site>
To: Florian Weimer <fw@deneb.enyo.de>, Xi Ruoyao via Libc-alpha
	 <libc-alpha@sourceware.org>
Cc: caiyinyu <caiyinyu@loongson.cn>, Wang Xuerui <i@xen0n.name>, Adhemerval
 Zanella Netto <adhemerval.zanella@linaro.org>, Andreas Schwab
 <schwab@suse.de>
Date: Fri, 24 Mar 2023 18:36:32 +0800
In-Reply-To: <87mt424h0y.fsf@mid.deneb.enyo.de>
References: <20230324072745.4138-1-xry111@xry111.site>
	 <87mt424h0y.fsf@mid.deneb.enyo.de>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.48.0 
MIME-Version: 1.0
X-Spam-Status: No, score=-1.2 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,LIKELY_SPAM_FROM,SPF_HELO_PASS,SPF_PASS,TXREP autolearn=no autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org
List-Id: <libc-alpha.sourceware.org>

On Fri, 2023-03-24 at 10:47 +0100, Florian Weimer wrote:
> * Xi Ruoyao via Libc-alpha:
>=20
> > Currently GCC generates highly sub-optimal code on architectures
> > where
> > the calling convention prefers registers for arugment passing.=C2=A0 Th=
is
> > is
>=20
> Typo: ar[gu]ment
>=20
> > LoongArch is benefited from this (saving about 430 CPU cycles per
> > syscall, though I won't call it a significant improvement because
> > syscall is "slow" in nature).=C2=A0 And in the future we may switch mor=
e
> > ports to use the generic syscall without a performance regression,
> > reducing the number of target-specific syscall.{c,S} files we need
> > to
> > maintain.
>=20
> Does this impact the open* and fcntl* wrappers as well?

Yes, on LoongArch all GARs are saved :(.  I'll see if it's possible to
avoid using va_list for them too.

--=20
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University