From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 79A5328687 for ; Thu, 21 Nov 2024 15:33:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732203229; cv=none; b=kgQtrbK3ExaoIAkMzhWHg0Qdz2vo+W6YoCjtIiTJ6xrZU9gFAlhXdFYZxdhQ8gNgSVajroPEReyyFPYNpNCMaZuqdsI/kCeXY7dox4W5nkUiYGzpZ001imjJUTOEwaAngiqQ35FVa8ljNjkDaz0CuceIinjxizFjzvh5CYmRoIU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732203229; c=relaxed/simple; bh=ERdNmGcyd6AZrmPF2szVswpz9H59VeJ7vDPFvPHzXDo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=aZhRzDJy0GsB6GbIGtRJlxYSoPW9xBVd2oJUKiMeSPPtzzlKiJfaIO3MUuaT7dgsokGfEbeeQVbK0oKHBLLpNFGUoQVkvbB3LK99gVvfty4bOlRifhZifjXCtNbAow47yjHdX7BbZe9pz871VVb2rcC9e7aZHgdEiGVagOIyn4M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=i3W6cHcz; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="i3W6cHcz" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=+zR524Tfj2aoQsJieN/ro7G3f5lXPpJtIlcJbnqYJw4=; b=i3W6cHczj/KRIdQ559Y8SBa6TZ owMOidxvKjmKpJH7y6lE0ZVlxHgBoXR/JlKrVoNjqNhIG58udqT3zXzyoG2IS1HDHa8XhNQTtXjRx gMj+iEc+LsHO+IH+RSwCCRkfcnRsfxKz1JB2FrW/BWiVCSadpuhGfguZtaNbPJDS3POB5gMTimOMd hX4JiWKfx693zPagawRrE/c0mch6Z2f/LKmRH4y9kVQX0EsHO0DO3gPU40hwCUT7ly7pPAqcrHzHG Qx6WqcwnhFxdJ7vJ5Jfvno91E37oLBM0w+8gByycZwVDoh42gJz/Slz1DpJ9t89O0g4qCy4SnSboz ZWl9sYAA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tE9BW-00000000aw1-3Jvs; Thu, 21 Nov 2024 15:33:34 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 339A330068B; Thu, 21 Nov 2024 16:33:34 +0100 (CET) Date: Thu, 21 Nov 2024 16:33:34 +0100 From: Peter Zijlstra To: Vadim Fedorenko Cc: Vadim Fedorenko , Borislav Petkov , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Thomas Gleixner , Yonghong Song , Mykola Lysenko , x86@kernel.org, bpf@vger.kernel.org, Martin KaFai Lau Subject: Re: [PATCH bpf-next v8 1/4] bpf: add bpf_get_cpu_time_counter kfunc Message-ID: <20241121153334.GN39245@noisy.programming.kicks-ass.net> References: <20241121000814.3821326-1-vadfed@meta.com> <20241121000814.3821326-2-vadfed@meta.com> <20241121113202.GG24774@noisy.programming.kicks-ass.net> <482d32d5-2caa-4759-b3b1-765678ac42a2@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <482d32d5-2caa-4759-b3b1-765678ac42a2@linux.dev> On Thu, Nov 21, 2024 at 06:35:39AM -0800, Vadim Fedorenko wrote: > On 21/11/2024 03:32, Peter Zijlstra wrote: > > On Wed, Nov 20, 2024 at 04:08:11PM -0800, Vadim Fedorenko wrote: > > > New kfunc to return ARCH-specific timecounter. For x86 BPF JIT converts > > > it into rdtsc ordered call. Other architectures will get JIT > > > implementation too if supported. The fallback is to > > > __arch_get_hw_counter(). > > > > Still not a single word as to *WHY* and what you're going to do with > > those values. > > > > NAK > > Did you have a chance to read cover letter? Cover letter is disposable and not retained when applying patches, as such I rarely read it.