From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id 91EF06B0069 for ; Wed, 9 Nov 2011 16:58:18 -0500 (EST) Date: Thu, 10 Nov 2011 08:58:03 +1100 From: NeilBrown Subject: Re: mdraid write performance in different kernels up to 3.0, 3.0 shows huge improvement Message-ID: <20111110085803.3f60c2d6@notabene.brown> In-Reply-To: References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/5RI3B1BoRMOV2ePMJ_Q6r3="; protocol="application/pgp-signature" Sender: owner-linux-mm@kvack.org List-ID: To: Mikael Abrahamsson Cc: linux-mm@kvack.org, linux-raid@vger.kernel.org --Sig_/5RI3B1BoRMOV2ePMJ_Q6r3= Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Tue, 8 Nov 2011 10:28:57 +0100 (CET) Mikael Abrahamsson wrote: >=20 > Hello. >=20 > I have been running mdraid->cryptsetup/LUKS->lvm->xfs on Ubuntu AMD64 wit= h=20 > RAID5 and now RAID6 for quite some time, dating back to 2.6.27. Around=20 > 2.6.32 I saw quite a bit of regression in write performance (probably the= =20 > implementation of barriers), 2.6.35 was acceptable, 2.6.38 was really=20 > really bad, and 3.0 is like a rocket. Best of them all. >=20 > I'm talking about 10-20x in different in write performance on my workload= ,=20 > in combination with the older kernels throwing me page allocation failure= s=20 > when the write load gets high, and also quite often the machine would jus= t=20 > freeze up and had to be rebooted. >=20 > With 2.6.38 I was down to 6-10 megabyte/s write speed, whereas 3.0 seem t= o=20 > give me 100+ megabyte/s with the exact same workload, I've seen up to 150= =20 > megabyte/s writes at good times. This is on a box with AES-NI, so the=20 > crypto is not the limiting factor. That is an amazing improvement. I wish I know what caused it I really have no idea. You have quite a deep stack there and the change could be anywher= e. Still, it is good to hear such positive reports - thanks! NeilBrown >=20 > I have from time to time sent out an email regarding my page allocation=20 > failures, but never really got any takers on trying to fault find it, my= =20 > tickets with ubuntu also never got any real attention. I haven't really=20 > pushed it super hard with 3.0, but I've thrown loads at it that would mak= e=20 > 2.6.38 lock up. >=20 > Just wanted to send in this success report that this finally seem to have= =20 > seen some really nice improvements! >=20 --Sig_/5RI3B1BoRMOV2ePMJ_Q6r3= Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBTrr3aznsnt1WYoG5AQJUjw//TK0D2Z+eBRTZRLpzBMDisnfvHKbm9OaE A3cXIA4zN+1tMBbHoanvfKQRpG8YF7wWWMUBlru32QoN+cM+yaUPouWkqZ6imb+8 unA6SvaqI/8Xodci5mS0Bn4bNBjYwAVYuKAF4a9DjjZpQcSwZwyYdMnDOhurMWTA MuViVj+tdV8aFuJuT5lRw5YZRlLWV1xmUPoRE8GLnyMW8MU/Bd01549RRa8Fz8yU rcgI0qlzGFtq207eRC0sbr8VOkCauYCSWrPKXweJXA5HupmTJakDS4uuFDpUOmix +HPTuIzgER/WPVJvHc5Hz1v26v+U6HPV897kMqywV/9w4cH2esVbHDewkiQUS0ik 00lvzepaeZ3KdxtKxanJhHOgO+KCmUyMbMOjObZWD/O+SHmbciVu19szD7dDD07g infUJO1gUc828q3TfPovrDIkuoH3ToKbJHd+c/Xs1Ew9E9qs2auQRQ1IIp7m1MdL FvEAmy8oomD9KF1avu4lwFo1wQ/TuekTcHYCF6RhQ6g2O9zK7eWwUm7b16Ud0ZPZ Qd8I7pJRsOQz1ceo6kiJqrMtU21vbw2qyjJhnfOMuAd5f4uWGzmahM8GbnKf/K+V CE4LoZ0Oje/XttJ/hVN7I3hEMcab8EUKczDmv48P5DtsZcfTfiZVON/ixbxT0rqT zZsofhTVahA= =aTJf -----END PGP SIGNATURE----- --Sig_/5RI3B1BoRMOV2ePMJ_Q6r3=-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org