search for: num_coroutines

[CC to qemu-devel since I'm obviously doing something wrong here, I'm just not sure what.] I was getting ready to add multiple threads to ‘qemu-img convert’ (the longest part of v2v conversions) when I noticed that it had them already! (To be fair this was only added in February this year so no wonder we didn't notice.) To enable parallel convert we would need to use the ‘qemu-img

...threads are just an implementation detail. The caller doing the reads and writes is not multi-threaded but a number of coroutines executing in a single thread. The qemu-img convert logic runs in coroutines from just one main loop thread in qemu-img.c:convert_do_copy(): for (i = 0; i < s->num_coroutines; i++) { s->co[i] = qemu_coroutine_create(convert_co_do_copy, s); s->wait_sector_num[i] = -1; qemu_coroutine_enter(s->co[i]); } while (s->running_coroutines) { main_loop_wait(false); } > > I did some testing to see what effect this has. For this I...

...detail. The caller doing the reads > and writes is not multi-threaded but a number of coroutines executing in > a single thread. > > The qemu-img convert logic runs in coroutines from just one main loop > thread in qemu-img.c:convert_do_copy(): > > for (i = 0; i < s->num_coroutines; i++) { > s->co[i] = qemu_coroutine_create(convert_co_do_copy, s); > s->wait_sector_num[i] = -1; > qemu_coroutine_enter(s->co[i]); > } > > while (s->running_coroutines) { > main_loop_wait(false); > } > >> I did some t...