From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: References: <20180518014754.23644-1-mareklindner@neomailbox.ch> <20180518014754.23644-7-mareklindner@neomailbox.ch> <20180521131711.GK7162@otheros> <1883169.6MDR23bMJo@sven-edge> From: Antonio Quartulli Message-ID: <41a3ff9a-d673-7114-f32b-5644e21b02cc@unstable.cc> Date: Sat, 4 Aug 2018 17:31:27 +0800 MIME-Version: 1.0 In-Reply-To: <1883169.6MDR23bMJo@sven-edge> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="47QfXUdu38DNKhPaYexUXS397Y9xsDMRk" Subject: Re: [B.A.T.M.A.N.] [PATCH v2 6/7] batman-adv: ELP - use tp meter to estimate the throughput if otherwise not available List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: The list for a Better Approach To Mobile Ad-hoc Networking , Sven Eckelmann Cc: "txt.file" , Marek Lindner This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --47QfXUdu38DNKhPaYexUXS397Y9xsDMRk Content-Type: multipart/mixed; boundary="zsqnDOo0OpNlN9Py4YWHG3iJOB6wbz4X2"; protected-headers="v1" From: Antonio Quartulli To: The list for a Better Approach To Mobile Ad-hoc Networking , Sven Eckelmann Cc: "txt.file" , Marek Lindner Message-ID: <41a3ff9a-d673-7114-f32b-5644e21b02cc@unstable.cc> Subject: Re: [B.A.T.M.A.N.] [PATCH v2 6/7] batman-adv: ELP - use tp meter to estimate the throughput if otherwise not available References: <20180518014754.23644-1-mareklindner@neomailbox.ch> <20180518014754.23644-7-mareklindner@neomailbox.ch> <20180521131711.GK7162@otheros> <1883169.6MDR23bMJo@sven-edge> In-Reply-To: <1883169.6MDR23bMJo@sven-edge> --zsqnDOo0OpNlN9Py4YWHG3iJOB6wbz4X2 Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: quoted-printable Hi, On 22/05/18 03:06, Sven Eckelmann wrote: > On Montag, 21. Mai 2018 15:17:11 CEST Linus L=FCssing wrote: >>> + throughput =3D total_bytes * 8 >> ilog2(test_time) / = 10; > [...] >> ----- > [...] >> >> throughput =3D total_bytes * 8 >> log_test_time / 10; >> >> // Straightforward approach? >> throughput2 =3D total_bytes * 8 / test_time * 1000 / 1024 / 10= 0; > [...] >> ----- >> $ ./test >> Result: 80000000 (log_test_time: 13) >> Result2: 156 >> $ file ./test >> ./test: ELF 32-bit LSB pie executable ARM, EABI5 version 1 (SYSV), dyn= amically linked, interpreter /lib/ld-linux-armhf.so.3, for GNU/Linux 3.2.= 0, BuildID[sha1]=3Dd18f32829cdd2bc42cf744cdcafde7cdbd315cb0, not stripped= >> ----- >=20 > Thanks for this small example program. Yes, there are parenthesis missi= ng in=20 > the calculation. Right now, following is calculated: >=20 > (total_bytes * 8) >> (ilog2(test_time) / 10); >=20 > But the author most likely wanted following precedence: >=20 > ((total_bytes * 8) >> ilog2(test_time)) / 10; >=20 > And together with the fixed unit, you would get: >=20 > (total_bytes * 8 >> ilog2(test_time) / 100; >=20 > Your example program would then show following result because the shift= ing=20 > stuff is still the wrong approach: >=20 > Result: 195 (log_test_time: 13) > Result2: 156 >=20 > The calculation still has to be changed to something like this to get=20 >=20 > // when 0.1 Mbit/s =3D=3D 100 kbit/s > throughput =3D total_bytes * 5; > do_div(throughput, test_time * 64); >=20 > // when 0.1 Mbit/s =3D=3D 102.4 kbit/s > throughput =3D total_bytes * 625; > do_div(throughput, test_time * 8192); >=20 > // when 0.1 Mbit/s =3D=3D 100 kbit/s, and 1kbit/s =3D=3D 1000 bit (= instead of 1024 bit): > throughput =3D total_bytes; > do_div(throughput, test_time * 125); >=20 > Please keep in mind that we must do a check of the divisor (for 0) befo= re=20 > doing this do_div. Thanks for the code and the correction :-) Yes, we wanted to avoid 64 bits explicit divisions and we assumed test_time would have been a power of 2 (otherwise we'd accept a small error). Anyway, the last case brought by Sven depicts what we want to implement. The patch will be changed accordingly. Cheers, --=20 Antonio Quartulli --zsqnDOo0OpNlN9Py4YWHG3iJOB6wbz4X2-- --47QfXUdu38DNKhPaYexUXS397Y9xsDMRk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEERdCuyFSHc3WdqS4EB6U8WA7yzXQFAltlcnAACgkQB6U8WA7y zXTt4RAAm3jCwwskCGtkOFv/ZkGbqpCZL16UGUS4CW+XCuuu+6vvevmmfG9iVNr/ zEmwr7Ag6VD/0wi8D1GpF+WMx3P6ZioZHcyTW4SHwG9RQRcsmrRwdn5ZSvx0spjW hkw8KNrzoI5B7MTX1Ur0AmhBEt1VnvCfyX39hcQdcXNM3kkUI83NV/gPiarKg7oL 3JSlKxf5kFKY7hcu4sMGb2xXok1nI5iUy8o1Gv15isbYpBl2M8b+6XmCwVUKAUbM JSO3RWARw5Rz20BK0iLuD41GCQGfes+1yVMQm8CNYs8T+6GXzVMj0+RYzXvEXVCp zAfJrTr1P+NXpF3cK+8W7flD+lApBfBcfZ+LsB8FmDtPYVMk7ylIS3nwq+9R+cMO odD9llk1NzNn+pmpxv7V1i3TC76UvpGlnw1m/ZPzYHVrgBSd3dcCIGHfxZni1Nux f1QacMh30vW0k3LpznCUieDdB0PuaKdp10Scm2iRM4jUqIQhYES8Qm32AtlzfbeB oe8PKQICnl2uTaz3GKMozyTOZr5SzV2vSkHRrWA1NGCor7i0pxqlSkPTNKNMNzOO i7/ULSRqIoA9dswMJxZ2vAIODPcWEy/vu6R0PTPOXRi6vkpsAtHiIldYjuCHm/Xk YC698VNX/JtkXlxfe9K8AI4fVgtmeM2Bl4Rnola2dpPmhH/A/yU= =wOiE -----END PGP SIGNATURE----- --47QfXUdu38DNKhPaYexUXS397Y9xsDMRk--