From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 09218145FE8 for ; Mon, 22 Apr 2024 10:40:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713782401; cv=none; b=VOjHOutHleVsDsMNhc3L1vYVqEqaGhb3BkozrYFHnuMwycq/NQ3K2ukk41IFuCbcvR2uf2cuJ6aypoRkLwvCYuXSfHkd0gnUGk//HKNZ3brTOk81vxP8EJPqwmluXRPCJgH4nQLYR//VFU7lr1BBZwqPpd0GIalps0EUZulH2nU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713782401; c=relaxed/simple; bh=k07GGGGw73NI4ykfphepd7Xa+ZUYGIiVGLbCho333GI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Uh2clsoZ3Z9jDZ2ysuh1GMasDCkCiiHfHuYu9tc9W0Tf/gkyIVemNS+q5//2I8SS52iY0DnAcsm2pPcfbxbvP7tQxwDfdQ+6DRNl4vLEBV7FQPvfHex+bS4D8a5v/taigynfpc1CUd+x0GoftEcFmiKrxF4nkz1pPPFxTAJ5YnE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Jg+DlrDs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Jg+DlrDs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF831C113CC; Mon, 22 Apr 2024 10:39:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713782400; bh=k07GGGGw73NI4ykfphepd7Xa+ZUYGIiVGLbCho333GI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Jg+DlrDsfrw0bx7jbAV5DCqGUIbS4iy0h/HY7unEZn1U4EODJIodDTAQIRFRaCod2 ZdZagtaz+PH+r0fJSpjjRFvtLw3WQESOSYeJONCXpBhqiIJaUbo4JpkmwDJM3OX0cf dtkzeM28B1BwerubwWG3lpaXLrGsZ8zLFWCglBU9TKY7az4i6cbSDDiYn7Lnm0U+B4 bYz6lQHiNqIC1Kee5510XbZ/9moJkcAt1pSti8wTLlUsaDfl87pevxwHKWUlgCmeWd +sks8alv15T1Tqz0KgL7LXiaQ26tSI9QwVk3jx0bC0RXL/XqRrYmh84X/RR9CJTDd9 8CGJkSDyUlBlQ== Message-ID: <8a0b7902-4b75-47cc-a22b-d3b97ecac22d@kernel.org> Date: Mon, 22 Apr 2024 12:39:58 +0200 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH bpf-next v4 3/3] selftests/bpf: Support nonblock for send_recv_data Content-Language: en-GB To: Geliang Tang , Mat Martineau Cc: mptcp@lists.linux.dev References: <9cd358958245f8ec87c4f553779aa4243f967a2f.1712729342.git.tanggeliang@kylinos.cn> <12aab271-da72-49b4-ac91-2091b6889856@linux.dev> <9475c2259b3d32774bc1488dd0d6004f7ddfbf13.camel@kernel.org> <52673f90-84c6-4e3d-9967-a3d0a7335c46@kernel.org> <7732f129e5c1c2ff128878be9b865115e1319b85.camel@kernel.org> <0017e477-3fcd-45de-917b-b58b3781ca9b@kernel.org> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; keydata= xsFNBFXj+ekBEADxVr99p2guPcqHFeI/JcFxls6KibzyZD5TQTyfuYlzEp7C7A9swoK5iCvf YBNdx5Xl74NLSgx6y/1NiMQGuKeu+2BmtnkiGxBNanfXcnl4L4Lzz+iXBvvbtCbynnnqDDqU c7SPFMpMesgpcu1xFt0F6bcxE+0ojRtSCZ5HDElKlHJNYtD1uwY4UYVGWUGCF/+cY1YLmtfb WdNb/SFo+Mp0HItfBC12qtDIXYvbfNUGVnA5jXeWMEyYhSNktLnpDL2gBUCsdbkov5VjiOX7 CRTkX0UgNWRjyFZwThaZADEvAOo12M5uSBk7h07yJ97gqvBtcx45IsJwfUJE4hy8qZqsA62A nTRflBvp647IXAiCcwWsEgE5AXKwA3aL6dcpVR17JXJ6nwHHnslVi8WesiqzUI9sbO/hXeXw TDSB+YhErbNOxvHqCzZEnGAAFf6ges26fRVyuU119AzO40sjdLV0l6LE7GshddyazWZf0iac nEhX9NKxGnuhMu5SXmo2poIQttJuYAvTVUNwQVEx/0yY5xmiuyqvXa+XT7NKJkOZSiAPlNt6 VffjgOP62S7M9wDShUghN3F7CPOrrRsOHWO/l6I/qJdUMW+MHSFYPfYiFXoLUZyPvNVCYSgs 3oQaFhHapq1f345XBtfG3fOYp1K2wTXd4ThFraTLl8PHxCn4ywARAQABzSRNYXR0aGlldSBC YWVydHMgPG1hdHR0YmVAa2VybmVsLm9yZz7CwZEEEwEIADsCGwMFCwkIBwIGFQoJCAsCBBYC AwECHgECF4AWIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZUDpDAIZAQAKCRD2t4JPQmmgcz33 EACjROM3nj9FGclR5AlyPUbAq/txEX7E0EFQCDtdLPrjBcLAoaYJIQUV8IDCcPjZMJy2ADp7 /zSwYba2rE2C9vRgjXZJNt21mySvKnnkPbNQGkNRl3TZAinO1Ddq3fp2c/GmYaW1NWFSfOmw MvB5CJaN0UK5l0/drnaA6Hxsu62V5UnpvxWgexqDuo0wfpEeP1PEqMNzyiVPvJ8bJxgM8qoC cpXLp1Rq/jq7pbUycY8GeYw2j+FVZJHlhL0w0Zm9CFHThHxRAm1tsIPc+oTorx7haXP+nN0J iqBXVAxLK2KxrHtMygim50xk2QpUotWYfZpRRv8dMygEPIB3f1Vi5JMwP4M47NZNdpqVkHrm jvcNuLfDgf/vqUvuXs2eA2/BkIHcOuAAbsvreX1WX1rTHmx5ud3OhsWQQRVL2rt+0p1DpROI 3Ob8F78W5rKr4HYvjX2Inpy3WahAm7FzUY184OyfPO/2zadKCqg8n01mWA9PXxs84bFEV2mP VzC5j6K8U3RNA6cb9bpE5bzXut6T2gxj6j+7TsgMQFhbyH/tZgpDjWvAiPZHb3sV29t8XaOF BwzqiI2AEkiWMySiHwCCMsIH9WUH7r7vpwROko89Tk+InpEbiphPjd7qAkyJ+tNIEWd1+MlX ZPtOaFLVHhLQ3PLFLkrU3+Yi3tXqpvLE3gO3LM7BTQRV4/npARAA5+u/Sx1n9anIqcgHpA7l 5SUCP1e/qF7n5DK8LiM10gYglgY0XHOBi0S7vHppH8hrtpizx+7t5DBdPJgVtR6SilyK0/mp 9nWHDhc9rwU3KmHYgFFsnX58eEmZxz2qsIY8juFor5r7kpcM5dRR9aB+HjlOOJJgyDxcJTwM 1ey4L/79P72wuXRhMibN14SX6TZzf+/XIOrM6TsULVJEIv1+NdczQbs6pBTpEK/G2apME7vf mjTsZU26Ezn+LDMX16lHTmIJi7Hlh7eifCGGM+g/AlDV6aWKFS+sBbwy+YoS0Zc3Yz8zrdbi Kzn3kbKd+99//mysSVsHaekQYyVvO0KD2KPKBs1S/ImrBb6XecqxGy/y/3HWHdngGEY2v2IP Qox7mAPznyKyXEfG+0rrVseZSEssKmY01IsgwwbmN9ZcqUKYNhjv67WMX7tNwiVbSrGLZoqf Xlgw4aAdnIMQyTW8nE6hH/Iwqay4S2str4HZtWwyWLitk7N+e+vxuK5qto4AxtB7VdimvKUs x6kQO5F3YWcC3vCXCgPwyV8133+fIR2L81R1L1q3swaEuh95vWj6iskxeNWSTyFAVKYYVskG V+OTtB71P1XCnb6AJCW9cKpC25+zxQqD2Zy0dK3u2RuKErajKBa/YWzuSaKAOkneFxG3LJIv Hl7iqPF+JDCjB5sAEQEAAcLBXwQYAQIACQUCVeP56QIbDAAKCRD2t4JPQmmgc5VnD/9YgbCr HR1FbMbm7td54UrYvZV/i7m3dIQNXK2e+Cbv5PXf19ce3XluaE+wA8D+vnIW5mbAAiojt3Mb 6p0WJS3QzbObzHNgAp3zy/L4lXwc6WW5vnpWAzqXFHP8D9PTpqvBALbXqL06smP47JqbyQxj Xf7D2rrPeIqbYmVY9da1KzMOVf3gReazYa89zZSdVkMojfWsbq05zwYU+SCWS3NiyF6QghbW voxbFwX1i/0xRwJiX9NNbRj1huVKQuS4W7rbWA87TrVQPXUAdkyd7FRYICNW+0gddysIwPoa KrLfx3Ba6Rpx0JznbrVOtXlihjl4KV8mtOPjYDY9u+8x412xXnlGl6AC4HLu2F3ECkamY4G6 UxejX+E6vW6Xe4n7H+rEX5UFgPRdYkS1TA/X3nMen9bouxNsvIJv7C6adZmMHqu/2azX7S7I vrxxySzOw9GxjoVTuzWMKWpDGP8n71IFeOot8JuPZtJ8omz+DZel+WCNZMVdVNLPOd5frqOv mpz0VhFAlNTjU1Vy0CnuxX3AM51J8dpdNyG0S8rADh6C8AKCDOfUstpq28/6oTaQv7QZdge0 JY6dglzGKnCi/zsmp2+1w559frz4+IC7j/igvJGX4KDDKUs0mlld8J2u2sBXv7CGxdzQoHaz lzVbFe7fduHbABmYz9cefQpO7wDE/Q== Organization: NGI0 Core In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 22/04/2024 12:34, Geliang Tang wrote: > On Mon, 2024-04-22 at 12:31 +0200, Matthieu Baerts wrote: >> On 22/04/2024 12:04, Geliang Tang wrote:> On Mon, 2024-04-22 at 11:45 >> +0200, Matthieu Baerts wrote: >> >> (...) >> >>>> I might be wrong, but with MPTCP schedulers, it is different: >>>> with >>>> non-blocking IO, EAGAIN can be seen, and this case needs to be >>>> handled. >>>> Actively waiting by retrying directly in the loop in case of >>>> EAGAIN >>>> is >>>> not recommended, but probably OK for the tests (still, might be >>>> good >>>> to >>>> add a comment to recommend polling instead). So here as well, >>>> such >>>> modifications can stay in our tree for the moment. >>>> >>>> Also, what is not clear to me is where we set the socket as the >>>> non-blocking one. Is it only done for MPTCP servers/clients? >>> >>> I didn't set the socket as non-block in the end. >>> >>> EAGAIN will be got no matter non-block flag is set or not. >> >> That's strange, no? When the userspace sends data with a blocking IO >> socket, it should not get EAGAIN, no? >> >>> In old version like "[mptcp-next,v7,0/5] setsockopt per subflow: >>> BPF": >>> >>> https://patchwork.kernel.org/project/mptcp/cover/cover.1712571740.git.tanggeliang@kylinos.cn/ >>> >>> "set_nonblock" is added in patch 2, and invoked in run_subflow() in >>> patch 3. >> >> I see, but the commit message of patch 2 doesn't explain why >> set_nonblock() is needed for MPTCP. I see it is used in patch 3, but >> is >> it really necessary? Maybe it was added for other reasons, that are >> no >> longer valid today? >> >>>>> I added a issue #487 to trace this issue. >> >> Please also note that we didn't have this issue for a while. When we >> had >> it, it is when KVM was not supported on the CI: >> >>  $ /opt/virtme/virtme-run (...) >>  Could not access KVM kernel module: No such file or directory >>  qemu-system-x86_64: failed to initialize kvm: No such file or >> directory >>  qemu-system-x86_64: falling back to tcg >> >> >> Maybe we had this issue because the VM was abnormally too slow, and >> we >> reached the 3 seconds timeout described by Martin in a previous >> message? >> If this is due to the "abnormally slow setup", maybe we don't need to >> do >> anything? >> >> In other words, can you (easily) reproduce the issue on your side? >> With >> or without KVM support? > > It's easy to reproduce by increasing total_bytes: Even without "set_nonblock()"? With what is in our tree, we don't do that. As I mentioned above, if 'send()' stops before the end with -1 and errno set to EAGAIN while the socket is supposed to wait for the transfer to be over (blocking IO), I guess there is a bug somewhere, but not in the tests, no? Cheers, Matt -- Sponsored by the NGI0 Core fund.