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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5BF98C5B555 for ; Mon, 2 Jun 2025 20:43:38 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uMBzq-0001lp-Kk; Mon, 02 Jun 2025 16:43:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uMBzo-0001lb-Ee for qemu-devel@nongnu.org; Mon, 02 Jun 2025 16:43:01 -0400 Received: from smtp-out1.suse.de ([195.135.223.130]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1uMBzm-0001X9-R1 for qemu-devel@nongnu.org; Mon, 02 Jun 2025 16:43:00 -0400 Received: from imap1.dmz-prg2.suse.org (unknown [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 7E57A211A1; Mon, 2 Jun 2025 20:42:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1748896976; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=CeMZ4q3dS470/5gtdawA2Wl5kNnvhDp3yyNdenq2Lxs=; b=w5INRhg++3fCxfhAJJ8I3RfrcpwsHOzfBodM9t6Uejh5svc8/iBRjBlYkhg7OnXRJEsitA mdcl4cUNDbQ0UvuI781VoSTqJ52hKLsORke7DyHhr2+kqp4T6WckGNX2wU0wQqrfAqfgEk LJ832pxrTaBVIarql+kcy5y60+yqXUY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1748896976; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=CeMZ4q3dS470/5gtdawA2Wl5kNnvhDp3yyNdenq2Lxs=; b=l2yYvnM6ofceLdT6KRCGlqDsj/sMyazF0wM30Mx+XPXKD1pZLnwLL+iwB8EoBGMApktNFL X7xua5raxM+1hbCA== Authentication-Results: smtp-out1.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1748896976; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=CeMZ4q3dS470/5gtdawA2Wl5kNnvhDp3yyNdenq2Lxs=; b=w5INRhg++3fCxfhAJJ8I3RfrcpwsHOzfBodM9t6Uejh5svc8/iBRjBlYkhg7OnXRJEsitA mdcl4cUNDbQ0UvuI781VoSTqJ52hKLsORke7DyHhr2+kqp4T6WckGNX2wU0wQqrfAqfgEk LJ832pxrTaBVIarql+kcy5y60+yqXUY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1748896976; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=CeMZ4q3dS470/5gtdawA2Wl5kNnvhDp3yyNdenq2Lxs=; b=l2yYvnM6ofceLdT6KRCGlqDsj/sMyazF0wM30Mx+XPXKD1pZLnwLL+iwB8EoBGMApktNFL X7xua5raxM+1hbCA== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id EC8FC136C7; Mon, 2 Jun 2025 20:42:55 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id fBrLKs8MPmhvXgAAD6G6ig (envelope-from ); Mon, 02 Jun 2025 20:42:55 +0000 From: Fabiano Rosas To: Peter Xu , qemu-devel@nongnu.org Cc: "Dr . David Alan Gilbert" , peterx@redhat.com, Alexey Perevalov , Juraj Marcin Subject: Re: [PATCH 04/13] migration/postcopy: Make all blocktime vars 64bits In-Reply-To: <20250527231248.1279174-5-peterx@redhat.com> References: <20250527231248.1279174-1-peterx@redhat.com> <20250527231248.1279174-5-peterx@redhat.com> Date: Mon, 02 Jun 2025 17:42:52 -0300 Message-ID: <87msap50z7.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain X-Spamd-Result: default: False [-4.30 / 50.00]; BAYES_HAM(-3.00)[99.99%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; MISSING_XM_UA(0.00)[]; TO_DN_SOME(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_FIVE(0.00)[6]; RCVD_COUNT_TWO(0.00)[2]; FUZZY_BLOCKED(0.00)[rspamd.com]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:mid, suse.de:email, imap1.dmz-prg2.suse.org:helo] Received-SPF: pass client-ip=195.135.223.130; envelope-from=farosas@suse.de; helo=smtp-out1.suse.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Peter Xu writes: > I am guessing it was used to be 32bits because of the atomic ops. Now all > the atomic ops are gone and we're protected by a mutex instead, it's ok we > can switch to 64 bits. > > Reasons to move over: > > - Allow further patches to change the unit from ms to us: with postcopy > preempt mode, we're really into hundreds of microseconds level on > blocktime. We'd better be able to trap those. > > - This also paves way for some other tricks that the original version > used to avoid overflows, e.g., start_time was almost only useful before > to make sure the sampled timestamp won't overflow a 32-bit field. > > - This prepares further reports on top of existing data collected, > e.g. average page fault latencies. When average operation is taken into > account, milliseconds are simply too coarse grained. > > When at it: > > - Rename page_fault_vcpu_time to vcpu_blocktime_start. > > - Rename vcpu_blocktime to vcpu_blocktime_total. > > - Touch up the trace-events to not dump blocktime ctx pointer > > Signed-off-by: Peter Xu Reviewed-by: Fabiano Rosas