qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Cc: Ahmed Karaman <ahmedkrmn@outlook.com>
Subject: [PATCH] configure: fix performance regression due to PIC objects
Date: Sat, 19 Sep 2020 11:56:39 -0400	[thread overview]
Message-ID: <20200919155639.1045857-1-pbonzini@redhat.com> (raw)

Because most files in QEMU are grouped into static libraries, Meson conservatively
compiles them with -fPIC.  This is overkill and produces slowdowns up to 20% on
some TCG tests.

As a stopgap measure, use the b_staticpic option to limit the slowdown to
--enable-pie.  https://github.com/mesonbuild/meson/pull/7760 will allow
us to use b_staticpic=false and let Meson do the right thing.

Reported-by: Ahmed Karaman <ahmedkrmn@outlook.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 configure | 1 +
 1 file changed, 1 insertion(+)

diff --git a/configure b/configure
index 0004c46525..0786144043 100755
--- a/configure
+++ b/configure
@@ -7414,6 +7414,7 @@ NINJA=${ninja:-$PWD/ninjatool} $meson setup \
         -Dwerror=$(if test "$werror" = yes; then echo true; else echo false; fi) \
         -Dstrip=$(if test "$strip_opt" = yes; then echo true; else echo false; fi) \
         -Db_pie=$(if test "$pie" = yes; then echo true; else echo false; fi) \
+        -Db_staticpic=$(if test "$pie" = yes; then echo true; else echo false; fi) \
         -Db_coverage=$(if test "$gcov" = yes; then echo true; else echo false; fi) \
 	-Dmalloc=$malloc -Dmalloc_trim=$malloc_trim -Dsparse=$sparse \
 	-Dkvm=$kvm -Dhax=$hax -Dwhpx=$whpx -Dhvf=$hvf \
-- 
2.26.2



             reply	other threads:[~2020-09-19 15:58 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-19 15:56 Paolo Bonzini [this message]
2020-09-19 16:02 ` [PATCH] configure: fix performance regression due to PIC objects Philippe Mathieu-Daudé
2020-09-21  0:41 ` Richard Henderson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200919155639.1045857-1-pbonzini@redhat.com \
    --to=pbonzini@redhat.com \
    --cc=ahmedkrmn@outlook.com \
    --cc=qemu-devel@nongnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).