From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 B604716C6A1 for ; Thu, 21 Nov 2024 11:32:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732188732; cv=none; b=l8h2uE/5x9lYlg8snY8tDQHjMgCJupPBb8aCVf8qEWUfcnKYy0LCpVvbL973zdFdq+B+7QfBNBGP7ruIU4ymnhLrJIjWLURq3pVIOJB9uwyIwufDK18X2kStBYF7FC+sh+ro7+N1owiBqmd4g4rFzN2M805F2hJEVtR0J7BwFeI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732188732; c=relaxed/simple; bh=2lpc/Dad8+OfdZH86z/hXAXDPzJIU4EkCpBANq20P4w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GhmBUNWnsIMnu5aeSbuv+sx/OK/z2NlZqmeLuavID2/Bsf4NwY4/l3YV6rqNEe7OWjkzEzhYxDi1nDHKaQAEtFeCF6GN6dWFmusSXcBSLQi/5YQxGkc5/lE58jNxc9HZ1tEKYv+EIL4Kx7v2hnHSj8W0hdokYEx6/ovgiBWu7FM= 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=IaMjaIe/; arc=none smtp.client-ip=90.155.50.34 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="IaMjaIe/" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=2lpc/Dad8+OfdZH86z/hXAXDPzJIU4EkCpBANq20P4w=; b=IaMjaIe/u0ZCYBfjybFH0HkyTh 0N6s1jwGFLXzzgxJ147QeBgdLxAwQ4lKAvUndH+3jym5PqR2VeJhFhRPPrPcZnpJOU1TgoPZCpPzH 9WGvMggrGO29qvo8jTRhoXa2bJoTca26G6EQPhkdfs4WJHWEBw6u6INn6YBtacDQlEzhqWtp/X4GU svBaOn42vIuzAkVDzEKES2y2i6F5G5dYNoFeBpuZvS7zyD+ef31DiQbJEUxoeWBFiEnH8ycpJOzzz pOZUuR2SKH8ZpB/z99gXEtIA15Gs8bVfIfpsYE+Ozmj6g3XiZUyC71OJZ4UPlz8AQMVZ4qfbwmnh5 s7PB22Og==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tE5Pm-00000006KBi-1B9l; Thu, 21 Nov 2024 11:32:03 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id BE6FD30068B; Thu, 21 Nov 2024 12:32:02 +0100 (CET) Date: Thu, 21 Nov 2024 12:32:02 +0100 From: Peter Zijlstra To: Vadim Fedorenko Cc: Borislav Petkov , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Thomas Gleixner , Yonghong Song , Vadim Fedorenko , 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: <20241121113202.GG24774@noisy.programming.kicks-ass.net> References: <20241121000814.3821326-1-vadfed@meta.com> <20241121000814.3821326-2-vadfed@meta.com> 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: <20241121000814.3821326-2-vadfed@meta.com> 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