On Fri, 24 Jul 2009, Linus Torvalds wrote: > > Never mind. I'm seeing even worse behavior on a laptop I just dug up > (another 4200 rpm harddisk). > > I'll dig some more. Yeah, it seems to be the loading overhead. I'm seeing a 'time git branch' take 1.2s in the cold-cache case, in a directory that isn't even a git directory. And 80% of it comes before we even get to 'main()'. Shared library loading, SELinux crud etc. A lot of it seems to be 'libfreebl3' and 'libselinux', which is some crazy sh*t. It seems to be all from 'curl' support. That seems _really_ sad. Lookie here: [torvalds@nehalem git]$ ldd git linux-vdso.so.1 => (0x00007fff61da7000) libcurl.so.4 => /usr/lib64/libcurl.so.4 (0x00007f2f1a498000) libz.so.1 => /lib64/libz.so.1 (0x0000003cdb800000) libcrypto.so.8 => /usr/lib64/libcrypto.so.8 (0x0000003ba7a00000) libpthread.so.0 => /lib64/libpthread.so.0 (0x0000003cdb400000) libc.so.6 => /lib64/libc.so.6 (0x0000003cda800000) libidn.so.11 => /lib64/libidn.so.11 (0x0000003ceaa00000) libssh2.so.1 => /usr/lib64/libssh2.so.1 (0x0000003ba8e00000) libldap-2.4.so.2 => /usr/lib64/libldap-2.4.so.2 (0x00007f2f1a250000) librt.so.1 => /lib64/librt.so.1 (0x0000003cdbc00000) libgssapi_krb5.so.2 => /usr/lib64/libgssapi_krb5.so.2 (0x0000003ce6e00000) libkrb5.so.3 => /usr/lib64/libkrb5.so.3 (0x0000003ce7e00000) libk5crypto.so.3 => /usr/lib64/libk5crypto.so.3 (0x0000003ce7200000) libcom_err.so.2 => /lib64/libcom_err.so.2 (0x0000003ce6a00000) libssl3.so => /lib64/libssl3.so (0x0000003490200000) libsmime3.so => /lib64/libsmime3.so (0x000000348fe00000) libnss3.so => /lib64/libnss3.so (0x000000348f600000) libplds4.so => /lib64/libplds4.so (0x0000003cbc800000) libplc4.so => /lib64/libplc4.so (0x0000003cbdc00000) libnspr4.so => /lib64/libnspr4.so (0x0000003cbd800000) libdl.so.2 => /lib64/libdl.so.2 (0x0000003cdb000000) /lib64/ld-linux-x86-64.so.2 (0x0000003cda400000) libssl.so.8 => /usr/lib64/libssl.so.8 (0x0000003ba7e00000) liblber-2.4.so.2 => /usr/lib64/liblber-2.4.so.2 (0x0000003ceee00000) libresolv.so.2 => /lib64/libresolv.so.2 (0x0000003ce5600000) libsasl2.so.2 => /usr/lib64/libsasl2.so.2 (0x00007f2f1a030000) libkrb5support.so.0 => /usr/lib64/libkrb5support.so.0 (0x0000003ce7a00000) libkeyutils.so.1 => /lib64/libkeyutils.so.1 (0x0000003ce7600000) libnssutil3.so => /lib64/libnssutil3.so (0x000000348fa00000) libcrypt.so.1 => /lib64/libcrypt.so.1 (0x00007f2f19df8000) libselinux.so.1 => /lib64/libselinux.so.1 (0x0000003cdc400000) libfreebl3.so => /lib64/libfreebl3.so (0x00007f2f19b99000) [torvalds@nehalem git]$ make -j16 NO_CURL=1 [torvalds@nehalem git]$ ldd git linux-vdso.so.1 => (0x00007fff2f960000) libz.so.1 => /lib64/libz.so.1 (0x0000003cdb800000) libcrypto.so.8 => /usr/lib64/libcrypto.so.8 (0x0000003ba7a00000) libpthread.so.0 => /lib64/libpthread.so.0 (0x0000003cdb400000) libc.so.6 => /lib64/libc.so.6 (0x0000003cda800000) libdl.so.2 => /lib64/libdl.so.2 (0x0000003cdb000000) /lib64/ld-linux-x86-64.so.2 (0x0000003cda400000) What a huge difference! And the NO_CURL version really does load a lot faster in cold-cache. We're not talking small differences: - compiled with NO_CURL, five runs of "echo 3 > /proc/sys/vm/drop_caches" followed by "time git branch": real 0m0.654s real 0m0.562s real 0m0.519s real 0m0.534s real 0m0.734s Total number of system calls: 194 - compiled with curl, same thing: real 0m1.503s real 0m1.455s real 0m1.267s real 0m1.819s real 0m0.985s Total number of system calls: 407! ie we're talking a _huge_ hit in startup times for that curl support. That's really really sad - especially considering how all the curl support is for very random occasional stuff. I never use it myself, for example, since I don't use http at all. And even for people who do, they only need it for non-local operations. I wonder if there is some way to only load the crazy curl stuff when we actually want open a http: connection. Linus -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html