Date: Mon, 9 Nov 2015 20:09:30 -0700 From: Warner Losh <imp@bsdimp.com> To: Ian Lepore <ian@FreeBSD.org> Cc: Eugene Grosbein <eugen@grosbein.net>, Adrian Chadd <adrian@freebsd.org>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org> Subject: Re: CPU underload Message-ID: <42B3546E-F0F5-4A66-AFF0-D16465343FF9@bsdimp.com> In-Reply-To: <1447091207.91534.481.camel@freebsd.org> References: <56348063.3090508@grosbein.net> <563500FC.8020201@grosbein.net> <CAJ-Vmo=EpmG6OJxq_v_mqKMF48h_B3K7vKqnnaKAi3x1s-uaWQ@mail.gmail.com> <5635148B.2070307@grosbein.net> <CAJ-VmomzkG8ZB0h1Qc=Oeny2ZOzQg1UirUprM_gmMy64F5ZRYw@mail.gmail.com> <56351AA6.80903@grosbein.net> <CAJ-VmomLen5p7ELejU7QtC5CO2j8hydb_CvdOqQsfaaMAtmdkA@mail.gmail.com> <563523CA.3040207@grosbein.net> <CAJ-Vmonpd8R5C%2BNvhOGFD1okkkit990DV8c4Dm%2BLmpZ2uFfVkA@mail.gmail.com> <56367686.4090801@grosbein.net> <CAJ-VmomtJ9eKfAJYfn4e2S1xWN8-YHo0M0KH-9V=VjNBf6vVVA@mail.gmail.com> <563707A0.3040700@grosbein.net> <CANCZdfrB0hkjmTU-9NzimBv=X_h-=bF0D2azBxg=9B=kmitv7Q@mail.gmail.com> <56370E1D.3040801@grosbein.net> <CAJ-Vmo=0vOAq8db_GeLWmdXr7xJdzUh44ZZJrQ9vVdpvzT9hiQ@mail.gmail.com> <563F5630.2000407@grosbein.net> <CAJ-Vmon8_kHeg3FOzK6T8amzF=-0ia0-Hb1ve2zZoEdgxrHO8g@mail.gmail.com> <563F938B.3070707@grosbein.net> <CAJ-Vmon=GwJhUaoS=AH5iOzEAdUUEcCz9%2BW6jdPq3h1TyXZ_3A@mail.gmail.com> <1447090771.91534.477.camel@freebsd.org> <5640DB0E.8010005@grosbein.net> <1447091207.91534.481.camel@freebsd.org>
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--Apple-Mail=_406BEEA5-8A00-4596-9CCD-6C4612E4B526 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On Nov 9, 2015, at 10:46 AM, Ian Lepore <ian@FreeBSD.org> wrote: >=20 > On Tue, 2015-11-10 at 00:42 +0700, Eugene Grosbein wrote: >> On 10.11.2015 00:39, Ian Lepore wrote: >>> On Sun, 2015-11-08 at 11:23 -0800, Adrian Chadd wrote: >>>> ok, what's the l1 cache size reported at boot up? >>>>=20 >>>> I think I may just bump them all to 64. >>>=20 >>> 64 is not some kind of magic panacea. The value needs to be set to >>> the >>> cache line size for the runtime platform. If the right value is >>> 32, >>> then setting it to 64 will just waste memory. If we ever have a universal kernel, 64 could run on either 32 or 64 byte cache lines. Since we don=E2=80=99t, this is largely correct. It = was mostly a quick and easy to test suggestion, it doesn=E2=80=99t matter = since: >>>> L1 d-cache: 4 ways of 256 sets, 32 bytes per line >> Is it for instruction cache or for data cache? >=20 > Only the data cache size matters for USB_HOST_ALIGN. Since we=E2=80=99re flushing the data cache, and we don=E2=80=99t want = the device visible part of the USB buffers to share a cache line with other data for the host to use about the device. Making it too big doesn=E2=80=99t help, and costs memory. Making it too small is fatal: usb simply won=E2=80=99t work. Why we don=E2=80=99t have a panic when the cache line size is larger than usb_host_align, and a warning when it is smaller is beyond me... Warner --Apple-Mail=_406BEEA5-8A00-4596-9CCD-6C4612E4B526 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJWQV/rAAoJEGwc0Sh9sBEAofcP/2CuPgnVWJ72D9KVEcOXHfZv +8+z7PyyZ7+pZ1kJMP7LEaL2Gou+zVC/9y+TkYcYvs191WvFVWcYxl8tyTrlz/Sn 2CpeD34FglLdINHSiMgpqe4QPzjpuZ9VjqxixLntTapyu87x0qm0iwoXUc3kX4Ay +LLvem+71mTbQby4Rvpp/g+DCIr5THGnChpKliThUbXnXaqAwzNx8yeEUwQ7acZ9 eywqBKR26UCiubic/evpd4EM3r/UdRRDCjHWde2VIYnEMTyzO7sQwmUfURpGBzZp unqPcDv62rEKcg45/O198Cq7kwC534JZRsQ/lODJ8F6a771sJaY/46YxuM4WGRf0 LCJW9dV8m4UPda9jGdJmZ15xK7Fmn9Mu4Lf0s2ZfR0R1NBryN6Axlf+gJBxJOa7q f8w8Suh7qy2l6TtbX0SyhR3Uk+bFH986eL52LHcO4vCvRRv/8SFI9pX0/L7tNLLx Tc6KRdz1PGBTlDr9bbfJt4SrFDW5x5uyX+gUio11fCv+RZx8tw7+P64Ti9H7HoeI LTVu1OgRldFqz2sR6CX8faKc3/l1COVN/dZya4/1b0A9JvfUxu0pbrXobO9WP6B2 83kRSbupdbh6XO2p58pKj5FpoCe5OyAjHB6ZK3zN6EKuNMrR2++SPWPEID0o9TdG vO2lyCt1swwK5TcqHkxV =sW1u -----END PGP SIGNATURE----- --Apple-Mail=_406BEEA5-8A00-4596-9CCD-6C4612E4B526--
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