Messages in this thread Patch in this message | | | Subject | [PATCH 3/3] OProfile: thread switching performance fix | From | John Levon <> | Date | Tue, 17 Jun 2003 15:53:55 +0100 |
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Avoid the linear list walk of get_exec_dcookie() when we've switched to a task using the same mm.
diff -Naur -X dontdiff linux-cvs/drivers/oprofile/buffer_sync.c linux-fixes/drivers/oprofile/buffer_sync.c --- linux-cvs/drivers/oprofile/buffer_sync.c 2003-06-15 02:06:38.000000000 +0100 +++ linux-fixes/drivers/oprofile/buffer_sync.c 2003-06-15 15:34:47.000000000 +0100 @@ -425,7 +425,7 @@ { struct mm_struct * mm = 0; struct task_struct * new; - unsigned long cookie; + unsigned long cookie = 0; int in_kernel = 1; unsigned int i; @@ -442,13 +442,15 @@ in_kernel = s->event; add_kernel_ctx_switch(s->event); } else { + struct mm_struct * oldmm = mm; + /* userspace context switch */ new = (struct task_struct *)s->event; - release_mm(mm); + release_mm(oldmm); mm = take_tasks_mm(new); - - cookie = get_exec_dcookie(mm); + if (mm != oldmm) + cookie = get_exec_dcookie(mm); add_user_ctx_switch(new, cookie); } } else { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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