linux-kernel - latencies due to disk writes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20070226015439.97500@gmx.net>
Date:	Mon, 26 Feb 2007 02:54:39 +0100
From:	kalium@....de
To:	linux-kernel@...r.kernel.org
Subject: latencies due to disk writes

Hello!

I'm experiencing extreme lags during disk writes. I have read somewhere (didn't save the URI, sigh) that this is actually related to bad (non-existing) write io priorities (CFQ only manages file reads).

I could imagine two quick, easy and probably quite effective ways to prevent such lags:

1.) don't flush buffers to disk at once more than necessary.

2.) relate CPU niceness to max write buffer fill level (ie. the point where it gets forced to be flushed to disk -- a conservative estimate would be much better than nothing): (100-5*nicelevel)%, ie. writes for processes having nice level 19 are blocked/delayed until the write buffer is below 5%. That way, the accounting is done at a higher and probably easier to access level.

Maybe I'm just talking nonsense, but nonetheless, here are my 2 cents.

Best regards,
Mark

p.s. please CC me as I'm not subscribed to this list.
-- 
"Feel free" - 10 GB Mailbox, 100 FreeSMS/Monat ...
Jetzt GMX TopMail testen: www.gmx.net/de/go/mailfooter/topmail-out
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/