From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793891104; b=HBtPVV9jHE6Zjt2TVix6atXCHxIUonHEQBZjMs/8MxIys/Fc/JSltE2vrOPcPz7JwoaR ci1UgPKLze9Xo5jhzvc9jIcPxfkyNVaxLFyUhUymWWslrUwfz3FAMpZFTR82+3IIb3Jt8 vC2iUO9zDQkzx4NwBIuLbKTNdFE/6NUxo768ComsUHjr6RORBpeisePSRCDEAL1SoN5wo Ynu/MCf/qOdHqwGxyQX8tPNscXsqBFu8P3Kc1kldU88/Oku0JCYPuRoEqFaIRP0LXiNyE +kEfk7AfGOeuQSYFtPscN9M5cEwZGJB2KR+F3zgyXzmtEqdl7R2gxL8XTyDCAHKSM+A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793891104; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition: Content-Transfer-Encoding:In-Reply-To; bh=IDZiEDQ2fJcCZR1mPomOrN1HJzC+gocV2xQLf/Xmqno=; b=ZINlSprPFoPW+BlDy2gFoGryyK4tbnD/wIiX0Vn3q/R2pUJzM8/bpl1AQiNzaDeltiFT k0nAo6OP5EM42uWZyUrUPR2WsKfuBgb41WJROA/2nFkAy7bFp5myirJ7pmgNasTOdZkj0 SQl3vxyNejgwG/4Q1CYbjOvf7oW7lSLkcNeU5v75c2/xvXBmFG35QBHEygew0C3t02ZLr cjMh/cPmWQgL4+DpJPweZTd7h8onnPQ81GICQSytR5ckJ+PBa4jecZwCQQ1bJQbumMV/y qIM/zqoNkElm5wyI50mJyUEPDapE30oxzTDBOHQQowNLmoEE1HYtrOUg3KxLj4NNAdA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=HrOw8A1j; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F1A96606A31B; Thu, 5 Nov 2026 15:05:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=HrOw8A1j Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA91E1F000C1; Thu, 5 Nov 2026 15:05:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793891103; bh=IDZiEDQ2fJcCZR1mPomOrN1HJzC+gocV2xQLf/Xmqno=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=HrOw8A1jlUuhJDo1BiAbNQGXgo0JMDDcCaPKHctvyeHpkOGNMXXK9/65YyKmpklzH rlN5wpQjCoPa3I+ssp3r4upL0cZMHwUddWnS+er5KF4ShJtKSv9Kxe6YZf3mMwZZk3 SAvN2djBmxXJM/XX59Q/5PMOX4NA/rclcaRZTHsB94oMDA9H2FUvtVycQHZv4ravfX pTPN7wyffQwgwU7ShR+nKJNKSvSQSozsE59O/DR2/496o73Wv2MkC9P0Nz5b06UeBZ hkcjkn1ly8s5Yerske8dk0Ck2Sdd7endvSjESEOiAwolQU3ipl9m0CjobIs3Cyi+9U SfdfwyVMM80WA== Date: Thu, 5 Nov 2026 16:04:58 +0100 From: Christian Brauner To: kernel test robot , Breno Leitao Cc: oe-lkp@lists.linux.dev, lkp@intel.com, linux-kernel@vger.kernel.org, Mateusz Guzik , Oleg Nesterov , linux-fsdevel@vger.kernel.org Subject: Re: [linus:master] [fs/pipe] f7f4665dc5: lmbench3.PIPE.bandwidth.MB/sec 18.5% regression Message-ID: <20261105-trommeln-einspannen-radius-ccb4e174e407@brauner> References: <202611041404.befe64cd-lkp@intel.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <202611041404.befe64cd-lkp@intel.com> On Thu, Nov 05, 2026 at 08:38:45AM +0800, kernel test robot wrote: > > > Hello, > > kernel test robot noticed a 18.5% regression of lmbench3.PIPE.bandwidth.MB/sec on: > > > commit: f7f4665dc520fd8bbc1db20e59945773e03744a0 ("fs/pipe: unify the page pools into a single per-pipe pool") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master @Breno can you reproduce this? It's something we should at least investigate. > > testcase: lmbench3 > config: x86_64-rhel-9.4 > compiler: gcc-14 > test machine: 224 threads 2 sockets Intel(R) Xeon(R) (Sapphire Rapids) with 128G memory > parameters: > > test_memory_size: 50% > nr_threads: 20% > mode: development > test: PIPE > cpufreq_governor: performance > > If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags > | Reported-by: kernel test robot > | Closes: https://lore.kernel.org/oe-lkp/202611041404.befe64cd-lkp@intel.com > > Details are as below: > --------------------------------------------------------------------------------------------------> > > The kernel config and materials to reproduce are available at: > https://download.01.org/0day-ci/archive/20261104/202611041404.befe64cd-lkp@intel.com > > ========================================================================================= > compiler/cpufreq_governor/kconfig/mode/nr_threads/rootfs/tbox_group/test/test_memory_size/testcase: > gcc-14/performance/x86_64-rhel-9.4/development/20%/debian-13-x86_64-20250902.cgz/lkp-spr-2sp2/PIPE/50%/lmbench3 > > commit: > c610d2d078 ("fs: annotate inode timestamp accessors") > f7f4665dc5 ("fs/pipe: unify the page pools into a single per-pipe pool") > > c610d2d0787961cd f7f4665dc520fd8bbc1db20e599 > ---------------- --------------------------- > %stddev %change %stddev > \ | \ > 29142 ± 2% -18.5% 23737 lmbench3.PIPE.bandwidth.MB/sec > 191.80 ± 8% +54.1% 295.65 ± 5% lmbench3.time.elapsed_time > 191.80 ± 8% +54.1% 295.65 ± 5% lmbench3.time.elapsed_time.max > 23261 ± 16% +19.3% 27743 ± 5% lmbench3.time.involuntary_context_switches > 9853 ± 16% +27.9% 12605 ± 5% lmbench3.time.system_time > 51.80 ± 2% +11.6% 57.80 ± 3% lmbench3.time.user_time > 2.928e+08 ± 3% +26.6% 3.706e+08 ± 4% lmbench3.time.voluntary_context_switches > > > Disclaimer: > Results have been estimated based on internal Intel analysis and are provided > for informational purposes only. Any difference in system hardware or software > design or configuration may affect actual performance. > > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests/wiki > > > --