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 72B2B1FE0EB for ; Wed, 13 Nov 2024 11:12:44 +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=1731496364; cv=none; b=QRL9R6FSS/xXSlVbCSdpSD4DSfABYyPE3sZIRKD7T/rChYZo6hDtcMJR11GMM5LEFf0fg/gNr22uzp3I8rIF1lH0em8ICGP8A+FEEmvU9RCNLk8Wh8H528MknVGt43No0rXGuK5J4v85LqlxWlB1EvL0I0w9Mm0gDvl1fkHwNHQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731496364; c=relaxed/simple; bh=mIGdVzGsC4Nk+b93weI7HLWPEXwroJOOnErhV0tcHrY=; h=From:To:Cc:Subject:References:Date:In-Reply-To:Message-ID: MIME-Version:Content-Type; b=IpNLv0HuRRdi+0xDsKAnhpEsmNMBExVfGcFXXL4mQTSXEbJesRZ6DomfK49M+dHtCd1CScPRmWhUYZ81XXKROAcf/9y2HF45X19ZF4GeRpCIV2yppLoYItb7PEZSlEnHLZtHd0CmOcB/WcW65OMbqYyhX7ohTUR/jAEJNZnSMBY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=A+Y/T4Dk; 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="A+Y/T4Dk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49629C4CECD; Wed, 13 Nov 2024 11:12:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731496364; bh=mIGdVzGsC4Nk+b93weI7HLWPEXwroJOOnErhV0tcHrY=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=A+Y/T4Dkar86c5J2gKa6jC48JAiRut7QMWQ7m0RBpXvd8maYY6xEX8xiIBFUFMC9+ +Ks29tuWTOdx/HUSI3rt1mALI2uMU0tvPpdGirD0R2ONKVSz38aQI3+jJs5dPMoypQ NZ7nL0eiIEG6szQhh8hQA2nGSIBmRjGtC9Lre/4GMIp/tp6yhrk6j4RQDcsXREZBrl /mMDjMYHnjMar3bSI5zAGb65JZqv126sGtqO3YKMtZyKxuAu/vG5cvDyf3sO1jzTHt lszd6fjsNONG0xg9egQ84NV4KXalXyfBV6X1Fyhq+zzmPfmQxPSzHmAz3EvS+R9V9G IFEPtEMkM3kAA== From: Kalle Valo To: Baochen Qiang Cc: , Subject: Re: [PATCH 1/6] wifi: ath11k: avoid burning CPU in ath11k_debugfs_fw_stats_request() References: <20241113015631.3105-1-quic_bqiang@quicinc.com> <20241113015631.3105-2-quic_bqiang@quicinc.com> Date: Wed, 13 Nov 2024 13:12:41 +0200 In-Reply-To: <20241113015631.3105-2-quic_bqiang@quicinc.com> (Baochen Qiang's message of "Wed, 13 Nov 2024 09:56:26 +0800") Message-ID: <877c972xqu.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) Precedence: bulk X-Mailing-List: linux-wireless@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Baochen Qiang writes: > We get report [1] that CPU is running a hot loop in > ath11k_debugfs_fw_stats_request(): > > 94.60% 0.00% i3status [kernel.kallsyms] [k] do_syscall_64 > | > --94.60%--do_syscall_64 > | > --94.55%--__sys_sendmsg > ___sys_sendmsg > ____sys_sendmsg > netlink_sendmsg > netlink_unicast > genl_rcv > netlink_rcv_skb > genl_rcv_msg > | > --94.55%--genl_family_rcv_msg_dumpit > __netlink_dump_start > netlink_dump > genl_dumpit > nl80211_dump_station > | > --94.55%--ieee80211_dump_station > sta_set_sinfo > | > --94.55%--ath11k_mac_op_sta_statistics > ath11k_debugfs_get_fw_stats > | > --94.55%--ath11k_debugfs_fw_stats_request > | > |--41.73%--_raw_spin_lock_bh > | > |--22.74%--__local_bh_enable_ip > | > |--9.22%--_raw_spin_unlock_bh > | > --6.66%--srso_alias_safe_ret > > This is because, if for whatever reason ar->fw_stats_done is not set by > ath11k_update_stats_event(), ath11k_debugfs_fw_stats_request() won't yield > CPU before an up to 3s timeout. > > Add 100ms sleep to avoid CPU burning. > > Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.37 > > Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices") > Reported-by: Yury Vostrikov > Closes: https://lore.kernel.org/all/7324ac7a-8b7a-42a5-aa19-de52138ff638@app.fastmail.com/ # [1] > Signed-off-by: Baochen Qiang > --- > drivers/net/wireless/ath/ath11k/debugfs.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/net/wireless/ath/ath11k/debugfs.c b/drivers/net/wireless/ath/ath11k/debugfs.c > index 57281a135dd7..a5e0f2092da5 100644 > --- a/drivers/net/wireless/ath/ath11k/debugfs.c > +++ b/drivers/net/wireless/ath/ath11k/debugfs.c > @@ -207,6 +207,9 @@ static int ath11k_debugfs_fw_stats_request(struct ath11k *ar, > break; > } > spin_unlock_bh(&ar->data_lock); > + > + /* 100ms is empirical, change if required */ > + msleep(100); > } > return 0; > } Please don't reinvent the wheel. Why not just use completion instead of this ugly spinning hack? -- https://patchwork.kernel.org/project/linux-wireless/list/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches