From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <pve-devel-bounces@lists.proxmox.com> Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) by lore.proxmox.com (Postfix) with ESMTPS id 47A991FF168 for <inbox@lore.proxmox.com>; Mon, 14 Oct 2024 11:07:19 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 4010830DF3; Mon, 14 Oct 2024 11:07:49 +0200 (CEST) Message-ID: <a4c5e7ba-f85c-4ed6-b25e-38851d7a476e@proxmox.com> Date: Mon, 14 Oct 2024 11:07:45 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta To: Proxmox VE development discussion <pve-devel@lists.proxmox.com>, Thomas Lamprecht <t.lamprecht@proxmox.com> References: <20240930114045.76730-1-f.schauer@proxmox.com> <e4a78a89-9b1d-48e0-8609-556752457ac4@proxmox.com> Content-Language: en-US From: Dominik Csapak <d.csapak@proxmox.com> In-Reply-To: <e4a78a89-9b1d-48e0-8609-556752457ac4@proxmox.com> X-SPAM-LEVEL: Spam detection results: 0 AWL 0.016 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment RCVD_IN_VALIDITY_CERTIFIED_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. 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SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: Re: [pve-devel] applied: [PATCH v2 common] tools: file_set_contents: use syswrite instead of print X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion <pve-devel.lists.proxmox.com> List-Unsubscribe: <https://lists.proxmox.com/cgi-bin/mailman/options/pve-devel>, <mailto:pve-devel-request@lists.proxmox.com?subject=unsubscribe> List-Archive: <http://lists.proxmox.com/pipermail/pve-devel/> List-Post: <mailto:pve-devel@lists.proxmox.com> List-Help: <mailto:pve-devel-request@lists.proxmox.com?subject=help> List-Subscribe: <https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel>, <mailto:pve-devel-request@lists.proxmox.com?subject=subscribe> Reply-To: Proxmox VE development discussion <pve-devel@lists.proxmox.com> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: pve-devel-bounces@lists.proxmox.com Sender: "pve-devel" <pve-devel-bounces@lists.proxmox.com> On 10/14/24 10:42, Thomas Lamprecht wrote: > Am 30/09/2024 um 13:40 schrieb Filip Schauer: >> The use of `print` can be inefficient for writing larger files due to >> its default buffering in 8 KiB blocks. >> >> This is especially problematic on `pmxcfs` where files are written in >> 4 KiB blocks due to the defaults of `libfuse2`. This leads to >> significant write amplification on files larger than 4 KiB. >> >> Patch (fix #5728: pmxcfs: allow bigger writes than 4k for fuse) [1] >> addresses this by enabling `big_writes`, allowing up to 128 KiB blocks. >> But due to the use of `print` in `file_set_contents`, writes are still >> only buffered in 8 KiB blocks. >> >> To further address this, this commit switches to using `syswrite` >> instead of `print` to mitigate the block size limit imposed by `print`. >> Combined with patch [1], file writes to `/etc/pve/` are now buffered in >> 128 KiB blocks. >> >> The table below illustrates the drastic reduction in write >> amplification when writing files of different sizes to `/etc/pve/` using >> `file_set_contents`: >> >> print big_writes+print big_writes+syswrite >> file size written amplif. written amplif. written amplif. >> 1 KiB 48 KiB 48.0 45 KiB 45.0 41 KiB 41.0 >> 2 KiB 48 KiB 24.0 45 KiB 22.5 62 KiB 31.0 >> 4 KiB 82 KiB 20.5 80 KiB 20.0 73 KiB 18.3 >> 8 KiB 121 KiB 15.1 90 KiB 11.3 89 KiB 11.1 >> 16 KiB 217 KiB 13.6 146 KiB 9.1 113 KiB 7.1 >> 32 KiB 506 KiB 15.8 314 KiB 9.8 158 KiB 4.9 >> 64 KiB 1472 KiB 23.0 826 KiB 12.9 259 KiB 4.0 >> 128 KiB 5585 KiB 43.6 3765 KiB 29.4 452 KiB 3.5 >> 256 KiB 20424 KiB 79.8 10743 KiB 42.0 2351 KiB 9.2 >> 512 KiB 86715 KiB 169.4 43650 KiB 85.3 3204 KiB 6.3 >> 1024 KiB 369568 KiB 360.9 187496 KiB 183.1 15845 KiB 15.5 >> >> Since `file_set_contents` also performs a `rename` after writing, the >> following table shows the results when the file is written without >> renaming it afterwards: >> >> print big_writes+print big_writes+syswrite >> file size written amplif. written amplif. written amplif. >> 1 KiB 29 KiB 29.0 29 KiB 29.0 25 KiB 25.0 >> 2 KiB 29 KiB 14.5 30 KiB 15.0 25 KiB 12.5 >> 4 KiB 37 KiB 9.3 44 KiB 11.0 41 KiB 10.3 >> 8 KiB 61 KiB 7.6 45 KiB 5.6 45 KiB 5.6 >> 16 KiB 143 KiB 8.9 86 KiB 5.4 57 KiB 3.6 >> 32 KiB 396 KiB 12.4 225 KiB 7.0 69 KiB 2.2 >> 64 KiB 1281 KiB 20.0 673 KiB 10.5 105 KiB 1.6 >> 128 KiB 4789 KiB 37.4 3478 KiB 27.2 169 KiB 1.3 >> 256 KiB 18868 KiB 73.7 9976 KiB 39.0 572 KiB 2.2 >> 512 KiB 79304 KiB 154.9 42714 KiB 83.4 2150 KiB 4.2 >> 1024 KiB 347929 KiB 339.8 182483 KiB 178.2 11133 KiB 10.9 >> >> [1] https://lists.proxmox.com/pipermail/pve-devel/2024-September/065396.html >> >> Signed-off-by: Filip Schauer <f.schauer@proxmox.com> >> --- >> Changes since v1: >> * Add benchmark results without rename to commit message >> * Fix "Wide character in syswrite" error by first encoding $data with print >> >> src/PVE/Tools.pm | 21 ++++++++++++++++++--- >> 1 file changed, 18 insertions(+), 3 deletions(-) >> >> > > applied, and many thanks for the detailed benchmarks! > hi since you applied this, we probably also want to apply the pmxcfs patch? (since without that, this patch does not really have an effect) should i send a new version (as non rfc) with a better commit message for that or is that not necessary from your POV ? _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel