From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 56542224B05; Thu, 12 Feb 2026 16:47:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770914849; cv=none; b=CLEA3ZNCpL5UE0BRezAenGKZsaGUqYRx9FxVnT1ItescKqr8rT83g+GGdT84FdCeeY4l+QN7zUY0j+3xHH92hpjVQigZDKCwPUgDw+vTNXSFXP+Xc/huF48QQWyPSOqh2X6Hz8/ONl8tCRV1d0M0RTYLMOzHnUDz7g5DrWKen6E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770914849; c=relaxed/simple; bh=s/DyEPe+77NoYsDIGpxy2seHogqaqunQv6TIiFOPDzI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kYpQhdZ7MYPThJyuzJmtbf48VJpWfqrCmbFIHMIivlAja5zGD4nKwLjr+kmiWDx3I2LB8PweQQoBUGV0sPq6yqwRtA44aDt+nIE8gpNZYf80tKdzHAnfrwljcIfqdWw8xw1L00MXHdLeJLiWeDwN+HEQc0AKqev/L/lRelpgikk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=N+K6lj3w; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=btvf8tIt; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="N+K6lj3w"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="btvf8tIt" Date: Thu, 12 Feb 2026 17:47:25 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1770914846; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=s/DyEPe+77NoYsDIGpxy2seHogqaqunQv6TIiFOPDzI=; b=N+K6lj3wl0VbioEZ2q8gSVvJkdOh63504F2+D57irJaU2pWVpxcMDwW9us2dAeOCkB/87C +QBuXkmNV+2uv2l5Rv6bomcRt4GBEOzbGtYteuiWnLRR3fLUbPgh1g1mHzovFydc/yjjds 9cPwYvdaVH8N7HpjkDlUQYYqs87NCmNd3vtohZSP0bkHKFo7bd0f7Iy4hwigfKarWD2LJY x+N/LBXH9JCfQHOV9/+6NjeFbfX+RZHl8VXpVRq/0He245+/CjNjude04vIqPCIjJnbMUI E0Z/y55krglNbf8fu8b+K/KNn2E2EACfL1AecxGuyPmjUed+yYkmWdEE5hanGw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1770914846; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=s/DyEPe+77NoYsDIGpxy2seHogqaqunQv6TIiFOPDzI=; b=btvf8tItfDYAqnNr2fTa3aIBM0VfbBgRuxc5XlsgCD+E/96PiUpsz5xehfp5OiFe9pqUAc nsEH/9rOuy4fCGBQ== From: Sebastian Andrzej Siewior To: Jakub Kicinski Cc: Jacob Keller , Kurt Kanzenbach , Willem de Bruijn , Vadim Fedorenko , Willem de Bruijn , Paolo Abeni , Eric Dumazet , "David S. Miller" , "Loktionov, Aleksandr" , "Nguyen, Anthony L" , "Kitszel, Przemyslaw" , Paul Menzel , "Gomes, Vinicius" , "netdev@vger.kernel.org" , Richard Cochran , "linux-kernel@vger.kernel.org" , Andrew Lunn , "intel-wired-lan@lists.osuosl.org" Subject: Re: [Intel-wired-lan] [PATCH iwl-next v3] igb: Retrieve Tx timestamp directly from interrupt for i210 Message-ID: <20260212164725.ltllw51l@linutronix.de> References: <20260209090621.GiZqTiMJ@linutronix.de> <8e762437-69f9-40d7-bb75-3a45bef1d5d6@linux.dev> <20260209114836.GPU-vnnh@linutronix.de> <78e2af2c-40e6-43f1-9471-42f350e69389@linux.dev> <20260210121207.9kLHroS0@linutronix.de> <87qzqr5vos.fsf@jax.kurt.home> <12520aac-c69a-41a0-9710-497392bc18f6@intel.com> <20260211134436.1e623034@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: <20260211134436.1e623034@kernel.org> On 2026-02-11 13:44:36 [-0800], Jakub Kicinski wrote: > On Wed, 11 Feb 2026 11:29:03 -0800 Jacob Keller wrote: > > > Moving the timestamping in IRQ looked like a good solution, because t= he > > > device already signals that the Tx timestamp is available now. No need > > > to schedule any worker/work at all. So, it'd be very nice if > > > skb_tstamp_tx() could be called from IRQ context. BTW other drivers l= ike > > > igc call this function in IRQ context as well. > >=20 > > Right. Reporting the timestamp from the interrupt is the simplest and= =20 > > lowest latency method. I know Miroslav had some situations and devices= =20 > > where it apparently caused more problems than it helped, though I don't= =20 > > believe anyone else has reproduced those? >=20 > There's a BH workqueue now, as a replacement for tasklets. > Presumably smallest fix would be to switch to that? Hmm. This would raise the TASKLET softirq from the interrupt handler and then handle it on the irq-exit path.=20 Let me look if that one lock can be removed first=E2=80=A6 Sebastian