Package: cvs Version: 2:1.12.13+real-30 Severity: important Dear Maintainer,
CVS has serious performance issues due to use of suboptimal Gnulib pagealign_alloc.c code. The way the CVS uses pagealign_xalloc() / pagealign_free() and stores the results in a list and the suboptimal code in Gnulib has a combined effect of consuming CPU time unnecessarily. In pathological cases CVS can be stuck in buf_free_datas() function for hours. In particular get_buffer_data() calls pagealign_xalloc(). pagealign_xalloc() itself stores the allocated memory in a linked list. Then buf_free_datas() will call pagealign_free() for each buffer_data node. pagealign_free() will again scan its internal list looking for the pointer. This is a O(n) operation, and since the CVS list and Gnulib pagealign_alloc.c list store the nodes in exactly opposite order, this results in n * (n - 1) / 2 unnecessary operations. For example, allocating 2GB buffers on a system with 4K pagesize it would lead to 137438691328 unnecessary operations, seriously bogging down the CVS process. Upstream Gnulib has released a fix to pagealign code here: https://cgit.git.savannah.gnu.org/cgit/gnulib.git/commit/?id=7c96b402be00117225a6943ab53bb9e5e6e2c02b I suggest Debian picks up on this change to remedy this performance issue. -- System Information: Debian Release: 13.1 APT prefers stable-updates APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable') Architecture: amd64 (x86_64) Kernel: Linux 6.12.43+deb13-amd64 (SMP w/8 CPU threads; PREEMPT) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set Shell: /bin/sh linked to /usr/bin/dash Init: sysvinit (via /sbin/init) LSM: AppArmor: enabled Versions of packages cvs depends on: ii adduser 3.152 ii libbsd0 0.12.2-2 ii libc6 2.41-12 ii libcrypt1 1:4.4.38-1 ii libgssapi-krb5-2 1.21.3-5 ii libkrb5-3 1.21.3-5 ii zlib1g 1:1.3.dfsg+really1.3.1-1+b1 Versions of packages cvs recommends: ii openssh-client 1:10.0p1-7 Versions of packages cvs suggests: pn mksh <none> pn rcs <none> -- no debconf information
