From owner-freebsd-hackers@freebsd.org Wed Jun 27 12:28:22 2018 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 3A19010215CD for ; Wed, 27 Jun 2018 12:28:22 +0000 (UTC) (envelope-from steevanxperia@gmail.com) Received: from mail-oi0-x22e.google.com (mail-oi0-x22e.google.com [IPv6:2607:f8b0:4003:c06::22e]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id B00B37B3B4 for ; Wed, 27 Jun 2018 12:28:21 +0000 (UTC) (envelope-from steevanxperia@gmail.com) Received: by mail-oi0-x22e.google.com with SMTP id r16-v6so1158953oie.3 for ; Wed, 27 Jun 2018 05:28:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=Cw+7/F5A1wfHkX+KplG5a0v7WgzthX2tuCmEPlo2NZw=; b=oBe2mUfvNjTlox3rbs4E59vZHxyYrOcbz/j6frLzU99ltAEuliDENPd/NpZVvXK0ho IJIWtLtagMkC5dYLjQ13x1YxVMdj+ijZeWkz8T2ROiuehwyX8XWgYYYMthzhQUs/wPXC kkPmo9Flm6wbK2mmUgKeIutqbm2pXd8a7L4Q1/BjNPYZa09W+uB5PO7x309sVNq6EUXL 9hhTTVmjXmDuQxZCSnamievy6/QTgiFNA60ceGdCwj4dApG0gTV0ycqfl6VjjOKrHU46 jT8n29d/MsPDw1QYLHGzE2+X93B2qoaCo4Pu9r186l9lsw0DuZYyw4W9seYHGJiNT4QD 2kag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=Cw+7/F5A1wfHkX+KplG5a0v7WgzthX2tuCmEPlo2NZw=; b=HUfiQmSKUUTBWdSdikUCe6Dto1ieNuYiEPGU/rwf7Hs3WNMIDf3+EcGMMwH40oy6xJ fLRb0hvOU2t7HDcwOHHBm3CqOxn21WCwU8cG8cPGIfxDB3Iac7vLivIxtkX72DXlZ9qd xK7TtXuzeUWnP+u5tp84kc/ngOlyV7M95NanXjVitkMoeICD9Ys5GSspVaj42O/iqBcG 1pbXZFYTOgjkbVP3z5rCDNSH63sEadnlsWo7TyiZGugLWa5bsOsEqNzQr7tRt6penJCZ wd+nC6krBv6XXCmThe8F6+5Yq6W5mU6uojbcglCBNZLHuorg+iBiJXPbio+RuFwx2tQT AjrA== X-Gm-Message-State: APt69E1BXxTIAAUonJs9ZZlgCygoDGqc9e8/C5dHUubq3NzYJ6h1ssne vcHubfl9c6qnH856wXrxrxadC+pNjezh62TlDrZYgw== X-Google-Smtp-Source: AAOMgpdz4EdFxpdwp+lKUcLFj+qK5dxCpTg6DVFV1dkyaVfL6k31zotHqDPaPH9N85bIoFdQ6S1IOdMXB7rwgJucSj4= X-Received: by 2002:aca:4e4d:: with SMTP id c74-v6mr3046363oib.16.1530102500611; Wed, 27 Jun 2018 05:28:20 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:ac9:73cf:0:0:0:0:0 with HTTP; Wed, 27 Jun 2018 05:28:20 -0700 (PDT) From: Steevan Rodrigues Date: Wed, 27 Jun 2018 17:58:20 +0530 Message-ID: Subject: high CPU usage in FreeBSD for a PCIe card driver To: freebsd-hackers@freebsd.org Content-Type: multipart/mixed; boundary="00000000000004f1b9056f9ec054" X-Content-Filtered-By: Mailman/MimeDel 2.1.26 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Jun 2018 12:28:22 -0000 --00000000000004f1b9056f9ec054 Content-Type: text/plain; charset="UTF-8" Hi I come from Linux background and new to FreeBSD. I am investigating a high CPU usage issue on FreeBSD for PCIe driver of a card . The card can process data at a rate of 30 to 50 Gbps . However, I see very high CPU usage even when I run a single threaded user side application which uses this card . I ran hotkernel script from Dtrace toolkit. A portion of the output is given in the attached file dtraceDiff.txt. Here I see that lock_delay seems to be the reason for high CPU usage. Looks like it comes from mutex locks This driver uses mutex locks ( mtx_lock). The CPU usage is very high on a multicore (Xeon CPU) server node than a dual core (Intel i3) Desktop . It shows 30 to 40 % CPU usage on a Intel i3 ( 2 core 4 threads) and 60 to 70% CPU usage on a Xeon CPU with 12 core (24 threads) for same output data rate . I wonder whether usage of mtx_lock is the cause of high CPU usage ? Any pointers or suggestions welcome. Using FreeBSD 11.1 Release Thanks Steev --00000000000004f1b9056f9ec054 Content-Type: text/plain; charset="US-ASCII"; name="dtraceDiff.txt" Content-Disposition: attachment; filename="dtraceDiff.txt" Content-Transfer-Encoding: base64 X-Attachment-Id: f_jix3g9dk0 LS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tCgpDUFUg dXNhZ2UgZGV0YWlscyBvbiBhICAxMiBjb3JlIDI0IHRocmVhZCBzZXJ2ZXIgUEMuIAoKcGFydCBv ZiB0aGUgcGVybCBob3RrZXJuZWwgIG91dHB1dCAKCmtlcm5lbGBmcmVlICAgICAgICAgICAgICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgIDEzMTQgICAwLjIlCmtlcm5lbGBfc3hfc2xv Y2sgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgIDE0MTUgICAwLjMlCmtl cm5lbGBkZXZfcmVsdGhyZWFkICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgIDE0 MzUgICAwLjMlCmtlcm5lbGBkZXZ2bl9yZWZ0aHJlYWQgICAgICAgICAgICAgICAgICAgICAgICAg ICAgICAgICAgIDE4NDIgICAwLjMlCmtlcm5lbGBfbXR4X2xvY2tfc3Bpbl9jb29raWUgICAgICAg ICAgICAgICAgICAgICAgICAgICAgIDIwNTkgICAwLjQlCmtlcm5lbGBjb3B5aW4gICAgICAgICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgIDIxNjQgICAwLjQlCmtlcm5lbGBhbWQ2 NF9zeXNjYWxsICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgIDIyMzUgICAwLjQl Cmtlcm5lbGBfX210eF9sb2NrX3NwaW5fZmxhZ3MgICAgICAgICAgICAgICAgICAgICAgICAgICAg IDM1NjYgICAwLjYlCmtlcm5lbGBiemVybyAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAg ICAgICAgICAgICAgIDQ4ODkgICAwLjklCmtlcm5lbGBfX210eF9sb2NrX3NsZWVwICAgICAgICAg ICAgICAgICAgICAgICAgICAgICAgICAgIDkzMjMgICAxLjclCmtlcm5lbGBhY3BpX2NwdV9pZGxl ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgMTExNjYgICAyLjAlCmtlcm5lbGBw bWFwX2V4dHJhY3QgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgMTc0OTEgICAz LjElCmtlcm5lbGBzcGlubG9ja19leGl0ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAg ICAgNjQ4NTAgIDExLjUlCmtlcm5lbGBjcHVfaWRsZSAgICAgICAgICAgICAgICAgICAgICAgICAg ICAgICAgICAgICAgICAxMzQ2MTcgIDIzLjklCmtlcm5lbGBsb2NrX2RlbGF5ICAgICAgICAgICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAyNjMzMzAgIDQ2LjglCgotLS0tLS0tLS0tLS0tLS0t LS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tCgpDUFUgdXNhZ2UgZGV0YWlscyBvbiBh ICAyIGNvcmUgNCB0aHJlYWQgSW50ZWwgaTMgYmFzZWQgRGVza3RvcCBQQy4gCgpwYXJ0IG9mIHRo ZSBwZXJsIGhvdGtlcm5lbCAgb3V0cHV0IAoKCmtlcm5lbGAweGZmZmZmZmZmODAgICAgICAgICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICA1NTggICAwLjYlCmtlcm5lbGBjb3B5b3V0ICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICA1OTIgICAwLjYlCjB4ZmZm ZmZmZmY4MjIzNjhhMyAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICA2Mzkg ICAwLjclCmtlcm5lbGBhbWQ2NF9zeXNjYWxsICAgICAgICAgICAgICAgICAgICAgICAgICAgICAg ICAgICAgICA2ODMgICAwLjclCmtlcm5lbGBfX210eF91bmxvY2tfZmxhZ3MgICAgICAgICAgICAg ICAgICAgICAgICAgICAgICAgICA3MjggICAwLjglCmtlcm5lbGBjb3B5aW4gICAgICAgICAgICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgIDEzMTEgICAxLjQlCmtlcm5lbGBiemVybyAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgIDE0MzQgICAxLjUlCmtl cm5lbGBwbWFwX2V4dHJhY3QgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgIDE2 MTUgICAxLjclCmtlcm5lbGBsb2NrX2RlbGF5ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAg ICAgICAgICAgIDIzMjkgICAyLjQlCjB4ZmZmZmZmZmY4MjJiMGI1ZSAgICAgICAgICAgICAgICAg ICAgICAgICAgICAgICAgICAgICAgIDI1MjggICAyLjYlCmtlcm5lbGBzcGlubG9ja19leGl0ICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgMjA5NTAgIDIxLjglCmtlcm5lbGBjcHVf aWRsZSAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgNDgxMjQgIDUwLjIl CgotLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0K --00000000000004f1b9056f9ec054--