From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1743C43381 for ; Thu, 7 Mar 2019 11:59:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C06EE20835 for ; Thu, 7 Mar 2019 11:59:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726496AbfCGL76 (ORCPT ); Thu, 7 Mar 2019 06:59:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:46832 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726101AbfCGL76 (ORCPT ); Thu, 7 Mar 2019 06:59:58 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B98BD2D805; Thu, 7 Mar 2019 11:59:57 +0000 (UTC) Received: from krava (unknown [10.43.17.112]) by smtp.corp.redhat.com (Postfix) with SMTP id 0F69E1001DD6; Thu, 7 Mar 2019 11:59:55 +0000 (UTC) Date: Thu, 7 Mar 2019 12:59:55 +0100 From: Jiri Olsa To: Alexey Budankov Cc: Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Peter Zijlstra , Ingo Molnar , Andi Kleen , linux-kernel Subject: Re: [PATCH v5 07/10] perf record: implement -z,--compression_level=n option and compression Message-ID: <20190307115955.GA29474@krava> References: <4d1b11a4-77ed-d9af-ed22-875fc17b6050@linux.intel.com> <87fa1906-2d6a-a00a-7ba5-b570d0cbf9cc@linux.intel.com> <20190305122622.GJ16615@krava> <6c964c70-86d7-32ab-c497-5ea65a9fd034@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6c964c70-86d7-32ab-c497-5ea65a9fd034@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Thu, 07 Mar 2019 11:59:57 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 07, 2019 at 11:26:16AM +0300, Alexey Budankov wrote: > > On 05.03.2019 15:26, Jiri Olsa wrote: > > On Fri, Mar 01, 2019 at 06:58:32PM +0300, Alexey Budankov wrote: > > > > SNIP > > > >> +static size_t record__process_comp_header(void *record, size_t increment) > >> +{ > >> + struct compressed_event *event = record; > >> + size_t size = sizeof(struct compressed_event); > >> + > >> + if (increment) { > >> + event->header.size += increment; > >> + return increment; > >> + } else { > >> + event->header.type = PERF_RECORD_COMPRESSED; > >> + event->header.size = size; > >> + return size; > >> + } > > > > so zstd_compress_stream_to_records calls this in the loop: > > > > while (input.pos < input.size) { > > ... > > size = process_header(record, 0); > > ... > > size = process_header(record, size); > > } > > > > the header.size will get overwritten with every new iteration, no? > > Every new record is headed by PERF_RECORD_COMPRESSED header an updated with > resulted compressed frame size after compression. > > process_header(, 0) puts header, then > compression puts compressed frame, then > process_header(, N) updates header.size value (+=). and then process_header(, 0) is called again no? jirka